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Abstract Clinical isolates (n = 63) of Pseudomonas aeruginosa obtained from various sites in 63 horses were compared using ERIC2 RAPD PCR to determine their genetic relatedness. Resulting banding patterns (n = 24 genotypes) showed a high degree of genetic heterogeneity amongst all isolates examined, indicating a relative non-clonal relationship between isolates from these patients, employing this genotyping technique. This study characterised 63 clinical isolates into 24 distinct genotypes, with the largest cluster (genotype E) accounting for 10/63 (15.9%) of the isolates. ERIC2 RAPD PCR proved to be a highly discriminatory molecular typing tool of P. aeruginosa in isolates recovered from horses. With the adoption of several controls to aid reproducibility, this technique may be useful as an alternative to PFGE, particularly in epidemiological investigations of outbreaks where speed may be a significant parameter. This is the first report of clonal heterogeneity amongst P. aeruginosa from horses and demonstrated that ERIC RAPD PCR is a rapid method for the examination of this species in horses, which may be useful in outbreak analysis.

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has now been described globally, as a clinically significant pathogen, particularly associated with skin and soft tissue infections, including abscesses, cellulitis and furunculosis. The recent emergence of CA-MRSA combined with its predominant presentation associated with skin and soft tissue infection, the previous literature indicating honey as an effective treatment of healthcare-associated HA-MRSA-related wound infection, as well as honey's ease of topical application, make the current study timely and of interest to healthcare practitioners involved with wound management. Although previous studies have examined the antimicrobial activity of honey against HA-MRSA, such data are limited regarding the activity of honey against this emerging type of MRSA. CA-MRSA (n=6 isolates), was examined for its susceptibility to natural honey (n=3 honey produced from bees in Northern Ireland and one commercial French honey). Results demonstrated that all honey was able to reduce the cultural count of all CA-MRSA from approximately 10(6) colony-forming units (cfus) (mean = 6.46 log10 cfu/g) to none detectable within 24h of co-culture of separate CA-MRSA organisms individually with all four-honey types examined. Subsequent non-selective enrichment of honey demonstrated that inoculated honey remained positive for CA-MRSA until 72h postinoculation, after which point no culturable organisms could be detected. This study demonstrated that, in vitro, these natural products had an antimicrobial activity against the CA-MRSA organisms tested. Further studies are now required to demonstrate if this antimicrobial activity has any clinical application. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the survival dynamics of several epidemic health care-associated (HA) and community-associated (CA) methicillin-resistant Staphylococcus aureus (MRSA) in planktonic state in widely employed denture-cleaning solutions. The bacteriocidal activity of five widely employed denture-cleaning formulations were examined against five phage-types of HA-MRSA (EMRSA 15, EMRSA 16, Irish 1, Irish 2, unique type), as well as a CA-MRSA strain, in this study. Viable MRSA cells (circa 10(5) cfu/mL) were coincubated with optimum recommended working concentrations of denture-cleaning solutions for up to 17 hours (overnight). Recovery experiments were unable to isolate any of the inoculated MRSA organisms 10 minutes post inoculation. The significance and impact of this short study indicates that HA-MRSA and CA-MRSA are not able to remain culturable for 10 minutes in planktonic form, in commonly used denture-cleaning formulations widely available on the UK High Street, suggesting that these formulations may be useful in lowering the numbers of MRSA. Further work is however required to examine the more complex survival dynamics of MRSA in naturally derived denture biofilm, associated with dental plaque and the use of such cleaning formulations. [ABSTRACT FROM AUTHOR]

BACKGROUND: Antibiotic agents have been in widespread and largely effective therapeutic use since their discovery in the 20th century. However, the emergence of multi-drug resistant pathogens now presents an increasing global challenge to both human and veterinary medicine. It is now widely acknowledged that there is a need to develop novel antimicrobial agents to minimize the threat of further antimicrobial resistance. With this in mind, a study was undertaken to examine the antimicrobial properties of aqueous extracts of 'exotic' Shiitake and Oyster mushrooms on a range of environmental and clinically important microorganisms. METHOD: Several batches of Shiitake and oyster mushrooms were purchased fresh from a local supermarket and underwent aqueous extraction of potential antimicrobial components. After reconstitution, aqueous extracts were tested qualitatively against a panel of 29 bacterial and 10 fungal pathogens, for the demonstration of microbial inhibition. RESULTS: Our data quantitatively showed that Shiitake mushroom extract had extensive antimicrobial activity against 85% of the organisms it was tested on, including 50% of the yeast and mould species in the trial. This compared favourably with the results from both the Positive control (Ciprofloxacin) and Oyster mushroom, in terms of the number of species inhibited by the activity of the metabolite(s) inherent to the Shiitake mushroom. CONCLUSIONS: This small scale study shows the potential antimicrobial effects of Shitake extracts, however further work to isolate and identify the active compound(s) now requires to be undertaken. Once these have been identified, suitable pharmaceutical delivery systems should be explored to allow concentrated extracts to be prepared and delivered optimally, rather than crude ingestion of raw material, which could promote further bacterial resistance. [ABSTRACT FROM AUTHOR]

Urinary tract infections (UTIs) are common infectious diseases in all ages of humans, from the neonate through to the elderly, with certain ages having an increasesed occurrence of specific bacterial etiologies. Clinical microbiology forms an important cornerstone in the scientific workup of (a) detecting a causal agent responsible for the UTI, (b) phenotypic and increasingly genotypic identification of causal agents of UTIs, and (c) characterization of identified agents of UTIs, including antibiotic susceptibility testing and virulence testing. For most clinicians, the workings of clinical microbiology remain a 'black box;' hence, the main objective of this review is to present scientific insight into how clinical microbiology handles the laboratory workup of urine specimens, and the pearls and pitfalls of urine micro-biology that may cause delay and frustration in the feedback of microbiology data to the patient's clinician. [ABSTRACT FROM AUTHOR]

The Gram-negative bacterium, Pseudomonas aeruginosa , is a major respiratory pathogen in patients with cystic fibrosis (CF), with an associated increase in morbidity and mortality. Consequently, infection prevention and control (IPC) plays an important role within health care in order to minimize the risk of cross-infection of this organism amongst patients and the hospital environment. It was the aim of this study to examine bacterial contamination of the health estate of CF in-patients' single-bedded rooms and related environments (n=40). Twelve bacterial genera were identified, six being Gram-positive (Brevibacterium, Dermacoccus, Micrococcus, Rothia, Staphylococcus and Streptococcus), and six being Gram-negative ( Acinetobacter, Citrobacter, Klebsiella, Moraxella, Pantoea and Pseudoxanthomonas). None of the organisms identified were considered of particular clinical significance to CF patients. The CF lung and associated sputa may be important reservoirs of Pseudomonas aeruginosa, with potential for spill-over into the health care estate. In the aftermath of the Pseudomonas neonatal outbreak at Altnagelvin and the Royal Jubilee Maternity Hospitals, where there was heightened IPC awareness regarding the presence of this bacterium, it is encouraging to note its absence from the CF-health care estate examined., Competing Interests: Provenance: externally peer reviewed., (Copyright © 2020 Ulster Medical Society.)

Competing Interests: Provenance: externally peer reviewed

Meningococcal disease has had devastating consequences in Northern Ireland since its first description locally in 1859. The incidence of this disease has significantly declined in recent years, however it is important to understand reasons for this changing epidemiology and to acknowledge the diagnostic and clinical management developments that have been made locally. This review aims to examine the changing face of this disease in Northern Ireland over the years, with particular reference to local disease prevention, epidemiology, diagnosis, clinical treatment and management, post-disease sequelae and the role of meningitis charities locally, in terms of patient support and research., Competing Interests: Provenance: externally peer reviewed

Competing Interests: Provenance: externally peer reviewed

Competing Interests: Provenance: externally peer reviewed

Competing Interests: Provenance: externally peer reviewed

In the British Isles, the frequency of rain results in the formation of puddles on footpaths and roads in/around hospitals. No data are available demonstrating the microbiological composition of such puddles and therefore a study was undertaken to examine the microbiology of puddles in the grounds of two tertiary university-teaching hospitals (18 sites) and compared with control puddles from non-hospital rural environments (eight sites), estimating (i) total viable count; (ii) identification of organisms in puddles; (iii) enumeration of Escherichia coli: (iv) detection of Extended Spectrum β-Lactamase producing organisms and (v) direct antimicrobial susceptibility testing. A mean count of 2·3 × 10 3  CFU per ml and 1·0 × 10 9  CFU per ml was obtained for hospital and non-hospital puddles respectively. Isolates (n = 77; 54 hospital and 23 non-hospital) were isolated comprising of 23 species among 17 genera (hospital sites), where the majority (10/16; 62·5%) of genera identified were Gram-negative approximately, a fifth (20·6%) were shared by hospital and non-hospital rural samples. Escherichia coli was detected in half of the hospital puddles and under-half (37·5%) of the rural puddles extended spectrum β-lactamase organisms were not detected in any samples examined. Rainwater puddles from the hospital and non-hospital environments contain a diverse range of bacteria, which are capable of causing infections., Significance and Impact of the Study: This study demonstrated the presence of a wide diversity of bacterial taxa associated with rainwater puddles around hospitals, many of which are capable of causing human disease. Of clinical significance is the presence of Pseudomonas aeruginosa isolated from a hospital puddle, particularly for patients with cystic fibrosis. The presence of potentially disease-causing bacteria in puddles in and around hospitals identifies a new potential environmental reservoir of bacteria. Furthermore work is now needed to define their potential of entering or exiting hospital wards by contaminated footwear., (© 2018 The Society for Applied Microbiology.)

What Is Known and Objective: Antibiotic resistance has become a global public health issue. Most antibiotics are prescribed in the community, although there is less stewardship of such agents in the community compared to secondary and tertiary care. Few studies have attempted to examine the prescribing practices in General Practice and its impact on antibiotic resistance and, therefore, a study was performed in order to compare antibiotic susceptibilities of commensal viridans group streptococci (VGS) obtained from patient cohorts in General Practices (GP), who were high and low prescribers of oral antibiotics., Method: Sixty-five patients (<1 month-81 years; 77% female: 23% male) were enrolled onto the study, and viridans group streptococci (n = 5/patient) were collected from each patient's nasal passages and oropharynx region and tested for antibiotic susceptibility against (i) tetracyclines (doxycycline); (ii) macrolides (erythromycin); (iii) β-lactams (penicillin G); and (iv) fluoroquinolones (ofloxacin & levofloxacin)., Results and Discussion: There were no significant differences in MICs between high and low GP prescribers with doxycycline (P = 0·094), erythromycin (P = 0·122), ofloxacin (P = 0·193) and levofloxacin (P = 0·058). However, there was a significant difference between high and low GP practices with regard to penicillin G (P = 0·031). This finding is important as the β-lactams are the most commonly prescribed oral antibiotic in the community., What Is New and Conclusion: This study demonstrates that high prescribing practices may lead to an altered (higher) level of resistance to these agents in the commensal VGS population, which may be important as reservoirs of antibiotic resistance determinants in subsequent horizontal gene transfer events, particularly with newly colonizing pathogens, including pneumococci. Primary care physicians should be aware that increased prescribing of antibiotics may led to increased level of penicillin resistance., (© 2015 John Wiley & Sons Ltd.)

A study was undertaken to compare a commercialized needle filter with a 0.2-μm filtered epidural set and a non-filtered standard needle. No culturable bacteria were detected following filtration through the 0.2-μm filter. Bacterial breakthrough was observed with the filtered needle (pore size 5 μm) and the non-filtered needle. Filtered systems (0.2 μm) should be employed to achieve total bacterial retention. This highlights that filtration systems with different pore sizes will have varying ability to retain bacteria. Healthcare professionals need to know what type/capability of filter is implied on labels used by manufacturers, and to assess whether the specification has the desired functionality to prevent bacterial translocation through needles., (Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)

The aim of this study was to examine the microbiological and related parameters (antibiotic resistance and pathogen identification) of water at two salmonid fish farms in Northern Ireland. Total Bacterial Counts at the Movanagher Fish Farm was 1730 colony forming units (cfu)/ml water (log10 3.24cfu/ml) and 3260cfu/ml (log10 3.51cfu/ml) at the Bushmills Salmon Station. Examination of resulting organisms revealed 10 morphological phenotypes, which were subsequently sequenced to determine their identification. All these organisms were Gram-negative and no Gram-positive organisms were isolated from any water sample. From these phenotypes, eight different genera were identified including Acinetobacter, Aeromonas, Chryseobacterium, Erwinia, Flavobacterium, Pseudomonas and Rheinheimera. One unnamed novel taxon was identified from water at the Movanagher Fish Farm, belonging to the genus Acinetobacter and has been tentatively named Acinetobacter movanagherensis. No other novel taxa were observed. All but one of these environmental organisms (Erwinia) are potential pathogens of fish disease. Total antibiotic resistance was observed to varying degrees in water specimens. The most resistant populations were observed in water taken from the Bushmills Salmon Station inlet, followed by water from the Movanagher Fish Farm. No resistance was observed against tetracycline and there was only one occurrence of resistance against ciprofloxacin. Overall, this study indicates that potential fish pathogens made up the majority of environmental organisms identified, even in the absence of recorded fish disease. There was also relatively high levels of total antibiotic resistance in the bacterial water populations examined, where tetracycline was the only antibiotic with zero resistance. These data indicate that the threat of bacterial disease is relatively close due to the indigenous colonization of farm water and that husbandry standards should be maintained at a high standard to avert bacterial disease outbreaks, rather than relying on the absence of specific pathogens in the immediate farm environment., (Copyright © 2014 Elsevier Inc. All rights reserved.)

What Is Known and Objective: To date, there is no evidence to indicate the reliability of how patients self-report their own antibiotic usage in the community. Such data are fundamental in supporting antimicrobial stewardship practices, and so there is a need to determine its accuracy and reliability., Comment: Patients in the community (n = 476) were required to recollect their antibiotic usage in the past three months. Simultaneously, similar information was obtained by careful extraction from their respective medical notes, which was qualitatively compared with the patient's recollection. Overall, concordance was high (88·1%), but age (<20 and >80 years) and sex (female) were significant factors of reliability., What Is New and Conclusion: This study suggests that basic self-reporting of antibiotic usage amongst patients is relatively reliable, with increasing accuracy with years until 80 years. Where such information is critical, the current study can help decide who to interview and whose notes to interrogate, in the quest to obtain reliable and accurate information., (© 2014 John Wiley & Sons Ltd.)

Aim: Recent UK National Institute for Health and Clinical Excellence guidelines state that there is no longer a need for oral antibiotic prophylaxis in patients undergoing dental procedures who are at risk of infective endocarditis (IE), and advocate the importance of maintaining good oral health. As viridans group streptococci (VGS) are common etiological agents of IE and inhabitants of the mouth, the purpose of this study was to examine the efficacy of common high-street mouthwashes against four classes of VGS organisms (salivarius, mitis, anginosus, and mutans groupings)., Methods: The survival of VGS, Streptococcus gordonii (National Collection of Type Cultures [NCTC] 7865), Streptococcus intermedius (NCTC 11324), Streptococcus mutans (NCTC 10449), Streptococcus oralis (NCTC 11427), Streptococcus pneumoniae (NCTC 7465, NCTC 7978, & American Type Culture Collection 49619) and Streptococcus salivarius (NCTC 8618) was assessed in vitro following treatment of approximately 10(7) c.f.u. in planktonic state with four mouthwashes., Results: No organisms were culturable following 1-min exposure, and were not recovered following non-selective enrichment following incubation in Brain Heart Infusion broth supplemented with 0.8% (w/v) yeast extract., Conclusions: These data indicate that such mouthwashes are able to completely kill VGS organisms tested in planktonic solution, where their use would promote good oral hygiene in patients at risk of IE., (© 2014 Wiley Publishing Asia Pty Ltd.)

A study was undertaken to examine the population structure of viridans group streptococci (VGS) isolated the upper respiratory tract of adult and paediatric patients within the community. VGS are common commensal bacterial inhabitants of the upper respiratory tract and valuable sentinel reporters of underlying antibiotic resistance (AR). Laboratory examination of the colonising VGS species may provide a valuable ecological description of the species isolated from the upper respiratory tract and their antibiotic susceptibility, including an estimation of the AR reservoir in this population. Freshly obtained nasal and oropharyngeal swabs from 84 patients were examined by selective conventional culture on Mitis-Salivarius agar and yielded 363 isolates of VGS. Sequence analyses of the rpnB and 16-23S rRNA ITS genes identified these isolates to belong to 10 species of VGS and included S. anginosus, S. australis, S. constellatus, S. infantis, S. mitis, S. oralis, S. parasanguinis, S. salivarius, S. sanguinis and S. vestibularis. The most frequent VGS organisms isolated was S. salivarius (282/363; 78.0%), followed by S. sanguinis (23/363; 6.3%), S. parasanguinis (21/363; 5.8%), S. mitis (18/363; 5.0%), S. anginosus (5/363; 1.4%), S. vestibularis (5/363; 1.4%), S. australis (3/363; 0.8%), S. oralis (3/363; 0.8%), S. infantis (1/363; 0.3%) and S. constellatus (1/363; 0.3%). All patients examined carried at least one VGS organism, where there were 17 combination patterns of carriage of the 10 species of VGS species isolated, where 54.2%, 37.3%, 7.2% and 1.2% of patients harboured one, two, three and four different VGS species, respectively. Antibiotic susceptibility was determined by standard disk diffusion assay testing against four classes of antibiotics, including the b-lactams [cefotaxime, cefuroxime], the tetracyclines [doxycycline], the fluoroquinolones [levofloxacin] and the macrolides [erythromycin]. Overall, there was no resistance to levofloxacin and cefuroxime, with limited resistance to cefotaxime (3.3%) and doxycycline (9.8%). Antibiotic resistance was highest in erythromycin, where 40.9% of isolates were resistant. S. vestibularis was the most antibiotic resistance of all VGS species examined (S. vestibularis v S. salivarius p=0.011), followed by S. anginosis. S. salivarius was the most antibiotic susceptible VGS species examined. Overall, given their infrequency in causing infection, relatively few studies to date have attempted to examine their ecology in their preferred body niche, namely the upper respiratory tract. However, knowing their prevalence is becoming increasingly important in relation to their ability to exclude significant respiratory pathogens, including Streptococcus pneumoniae. In conclusion, these data indicate that VGS colonisation of the upper respiratory tract in individuals within the community is dominated mainly with relatively antibiotic susceptible S. salivarius.

Objectives: The involvement of the peripheral nervous system by anti-CV2/CRMP5 paraneoplastic antibodies is typically encountered as a mixed sensorimotor polyneuropathy. We report a fatal case of severe chronic progressive axonal polyradiculoneuropathy in association with this antibody., Methods: Review of the patient's chart, nerve conduction/electromyographic studies, and nerve biopsy., Results: A 51-year-old man presented with a progressive quadriparesis over a 4-month period. Extensive evaluation for potential etiologies was significant only for positive anti-CV2/CRMP5 antibodies without detection of an underlying neoplasm. Despite multiple immunomodulatory therapies, the patient progressed and demonstrated electrodiagnostic evidence for a chronic axonal polyradiculoneuropathy with ongoing denervation. The patient eventually died of respiratory failure., Conclusions: This case adds to the clinical spectrum of the peripheral nervous system involvement in patients with paraneoplastic anti-CV2/CRMP5 antibodies.

Systemic sclerosis (SSc) or scleroderma is a connective tissue disease with a diverse array of clinical manifestations secondary to underlying fibrosis and autoimmunity. Central nervous system (CNS) impairment is uncommon in SSc. Here we report the fourth known patient with CNS vasculitis caused by SSc. In each previous report, the patient was a middle-aged to elderly female. Our patient was 24 years old at the time of presentation, significantly younger than the other reported patients. Importantly, our patient's rapidly progressive clinical course and poor response to immunosuppression have not been reported in patients with CNS vasculitis secondary to scleroderma. Although CNS vasculitis is extremely rare in SSc, our report suggests that clinicians should consider this diagnosis in the differential of SSc patients with neurologic impairment., (Published by Elsevier Ltd.)

Current autoclaving practices are designed to kill bacteria. Little is known about the effect of autoclaving on the integrity of bacterial genomic DNA. An experiment was performed to examine the effect of standard autoclaving on the integrity of bacterial DNA, employing polymerase chain reaction (PCR) as an indicator of DNA integrity. Amplifiable PCR signal was observed at t = 10, 20 and 30 min autoclaving time for Pseudomonas aeruginosa NCTC 10662; at t = 10, 20, 30 and 40 min for Salmonella Nottingham NCTC 7832; and at t = 10 and 20 min for Escherichia coli NCTC 9001. Careful consideration should therefore be given to residual molecular artefacts in future risk and environmental impact assessments, where the legacy of residual genomic DNA from dead bacterial and higher organisms may act as a potential reservoir, thereby feeding horizontal gene transfer scenarios in viable cells with potential hazardous genes of virulence, persistence or antibiotic resistance characteristics., (Copyright © 2012 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.)

Infarctions of the corpus callosum are rare. The clinical picture varies from an acute onset to slow evolving symptoms, frequently with poor localizing signs; however, the location of the infarct in the callosum often correlates with a specific etiology. We describe three patients with varying degrees of callosal infarction, each corresponding to a particular etiology., (Published by Elsevier Ltd.)

Aim: Previous work has indicated that environmental stresses on bacteria might lead to an upregulation of stress response. LED curing lights (315-400 nm) and other UV lights used in tooth whitening cosmetic procedures might act as stresses. We examined the effect of UV-C light, as a high-energy surrogate to the lower-energy UV-A light used in such instruments, to examine its effect on the antibiotic susceptibility of viridans group streptococci., Methods: Twelve species of viridans group streptococci were examined in this study: Streptococcus anginosus, Streptococcus australis, Streptococcus cristatus, Streptococcus gordonii, Streptococcus infantis, Streptococcus mitis, Streptococcus mutans, Streptococcus oralis, Streptococcus parasanguinis, Streptococcus pneumoniae, Streptococcus salivarius, and Streptococcus sanguinis. These organisms were exposed to varying degrees of sublethal UV-C radiation, and their minimum inhibitory concentration susceptibility was determined by broth dilution assay against three classes of commonly-used antibiotics: β-lactams (penicillin), macrolides (erythromycin), and fluoroquinolones (ciprofloxacin)., Results: There was no significant difference between antibiotic susceptibility before UV-C exposure and following maximum sublethal stress, prior to cell death due to fatal UV-C exposure., Conclusions: Exposure to UV-C light will not result in altered antibiotic susceptibility patterns on viridans group streptococci. Given that UV-C is more toxic and mutagenic than UV-A light, it is unlikely than UV-A light would yield any difference in response to such exposure., (© 2011 Blackwell Publishing Asia Pty Ltd.)

Skin tanning, either by exposure to natural sunlight or through use of UV sunbeds, has become a popular practice in the US, where it is estimated that approximately 1 million times per day someone in the US uses UV radiation for skin tanning, equating to 30 million Americans (circa 10% of the US population) who use a tanning bed. As well as exposing the host to periods of UV radiation, such practices also expose commensal skin bacteria, including Staphylococcus aureus, to such UV radiation. Previous work has indicated that environmental stresses on bacteria may lead to an upregulation of stress responses, in an attempt for the organism to combat the applied stress and remain viable. UV light may act as an environmental stress on bacteria, and so it was the aim of this study to examine the effect of UVc light on the antibiotic susceptibility of commensal skin bacteria, to determine if UV radiation would increase the antibiotic resistance of such skin flora and thus lead to a potential skin flora with increased antibiotic resistance. Previously, it has been shown that UVc light has a greater mutational effect on bacteria compared to lower-energy UV forms, including UVa and UVb light. Therefore, we decided to employ UVc light in our study to amplify the potential for mutational events occurring in skin staphylococci organisms (n=8) including methicillin-sensitive Staphylococcus aureus (n=2), methicillin-resistant Staphylococcus aureus (n=4), and coagulase-negative staphylococci (Staphylococcus haemolyticus) (n=2) were exposed to varying degrees of sublethal radiation via UVc light, and their minimum inhibitory concentration (MIC) susceptibility was determined by broth dilution assay against three classes of commonly used antibiotics, namely β-lactams (penicillin), macrolides (erythromycin), and fluoroquinolones (ciprofloxacin). There was no significant difference between antibiotic susceptibility before UVc exposure and until maximum sublethal stress, prior to cell death due to fatal UVc exposure with the cells. These results indicate that UV environmental stress/exposure does not upregulate antibiotic resistance, and therefore these data indicate that UVc radiation does not lead to a more antibiotic-resistant population in the staphylococci organisms post-exposure.

Antibiotic resistance in clinical pathogens in humans may be traced back to resistance mechanisms in environmental bacteria and any factors, which are likely to alter (upregulate) resistance in environmental organisms, is of potential and eventual consequence to human pathogens. Furthermore, sublethal doses of gamma radiation to environmental organisms may cause sublethal stress and a selective pressure, which may lead to mutational events that alter the bacterium's susceptibility profile. A gamma (γ) radiation simulation experiment was performed to emulate the exposure of four environmental bacteria, including Listeria innocua, Bacillus subtilis, E. coli and Pseudomonas aeruginosa, to levels of radiation in and around Fukushima, Japan, equating to 1, 10 and 100 years equivalence exposure. Alteration to susceptibility to 14 antibiotics was measured as the primary endpoint. There was no significant alteration in the susceptibility of the Gram-positive organisms, whereas both Gram-negative organisms became slightly more susceptible to the antibiotics tested over time. These data indicate that such radiation exposure will not increase the antibiotic resistance profile of these organisms and hence not add to the global public health burden of increased antibiotic resistance in human bacterial pathogens., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Streptococcus pneumoniae is the leading cause of community-acquired pneumonia (CAP). Currently, empirical treatment with quinolones is being used due to the emergence of beta-lactam and macrolide resistance in S. pneumonaie. Although the prevalence of quinolone-resistant S. pneumoniae remains low, increasing numbers of resistant isolates are being seen. Genetic mechanisms leading to fluoroquinolone resistance in pneumococci are complex. This study aims to use molecular methods to characterise all isolates through sequence analysis of their QRDR regions. Thirty-two S. pneumoniae isolates were obtained from nasal swabs from adult and paediatric patients attending local general practices in Northern Ireland. Phenotypic minimum inhibitory concentration (MIC) was determined for Clinical and Laboratory Standards Institute (CLSI) broth microdilution against ciprofloxacin, levofloxacin and norfloxacin. Simultaneously, the QRDR regions of gyrA, gyrB, parC and parE were analysed by sequence typing for all pneumococci obtained. Only one isolate (3.1%) showed reduced susceptibility to ciprofloxacin and levofloxacin. Two amino acid positions were discordant in the S. pneumoniae R6 strain and eight (25%) and 23 (71.9%) isolates contained the mutations Ile460Val in gyrA and Lys137Asn in parC (deposited in GenBank, accession numbers GQ999587-GQ999589), respectively. No mutations were found in either the gyrB or parE loci. In conclusion, the study demonstrated increased fluoroquinolone resistance which could not be accounted for simply through QRDR mutations, and, reciprocally, that mutations in the QRDR region do not necessarily result in overt phenotypic resistance.

Inadvertent exposure of bacterial pathogens to X-ray radiation may be an environmental stress, where the bacterium may respond by increasing mutational events, thereby potentially resulting in increased antibiotic resistance and alteration to genotypic profile. In order to examine this, four clinical pathogens, including the Gram-negative organisms Escherichia coli O157:H7 NCTC12900 and Pseudomonas aeruginosa NCTC10662, as well as the Gram-positive organisms Staphylococcus aureus NCTC6571 and Enterococcus faecium were exposed to X-rays (35,495 cGy/cm2) over a seven-day period. Antibiotic susceptibility was assessed before, during and after exposure by examining susceptibility, as quantified by E-test with six antibiotics, as well as to a further 11 antibiotics by measurement of susceptibility zone sizes (mm). Additionally, the DNA profile of each organism was compared before, during and after exposure employing the enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC PCR). Results indicated that exposure of these organisms to this amount of X-ray radiation did not alter their antibiotic susceptibility, nor their genomic DNA profile. Overall, these data indicate that exposure of bacteria to X-ray radiation does not alter the test organisms' antibiotic susceptibility profiles, nor alter genomic DNA profiles of bacteria, which therefore does not compromise molecular epidemiological tracking of bacteria within healthcare environments in which patients have been exposed to X-ray radiation.

Although about 75-80% of neutropenic fevers are thought to be caused by infections, a causal organism can be confirmed microbiologically or suspected clinically in only 30-50%, and even fewer of these cases (16%) have a documented bacteraemia. The cause of neutropenic fever in the remaining cases remains elusive. The reasons for this failure may be due to the difficulty in recovering low numbers of organisms, fastidious organisms which fail to grow using conventional culture media, the presence of non-culturable organisms, or the presence of inhibitory substances in specimens. Previously, the authors showed the presence of Acinetobacter in peripheral blood of febrile neutropenic patients with a haematological malignancy, using 16S rDNA polymerase chain reaction (PCR) and sequencing techniques. However, conventional culture was unable to detect these organisms. Hence, it was felt necessary to examine the antibacterial properties of four antineoplastic agents used in the treatment of haematological malignancy, namely bleomycin, cisplatin, doxorubicin and vincristine. A total of 56 wild-type Acinetobacter including seven species (A. calcoaceticus [n=17], A. septicus [n=11], A. baumannii [n=10], A. johnsonii [n=7], A. lwoffii [n=8] A. haemolyticus [n=2] and A. radioresistens [n=1]) were examined for their susceptibility to the four antineoplastic agents at therapeutic concentration. No inhibition was observed, but inhibition was seen at higher concentrations of both bleomycin and doxorubicin. Time to detection of blood culture bottles containing separate antineoplastic agents (i.e., bleomycin and doxorubicin) was compared to that containing saline using a paired t-test. Samples containing doxorubicin at 1 pg/mL were shown to have a mean time to detection of 21.8 h (range: 15.6-31.4 h). Bottles containing saline had a mean time to detection of 22.9 h (range: 18.2-31.3 h). Statistical analysis showed no significant difference (P=0.3361) between time to detection for blood culture bottles containing doxorubicin at achievable plasma concentration and corresponding negative controls. With regard to bleomycin (300 miu/mL), the mean time to detection was 27.29 h (range: 20.2-38.4 h) in the test bottles, with mean time to detection in the saline negative controls of 22.56 h (range: 17.0-30.1 h). Paired t-test gave P=0.000451, hence a significant difference in time to detection for blood cultures containing therapeutic levels of bleomycin. Overall, the antineoplastic agents vincristine, cisplatin or doxorubicin did not have any inhibitory effects on the Acinetobacter organisms examined. At worst, therapeutic concentrations of bleomycin may delay automated detection of an Acinetobacter bacteraemia by a mean time of 5.9 h.