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Within cystic fibrosis microbiology, there is often mismatch between the antibiotic susceptibility result of an isolated bacterial pathogen and the clinical outcome, when the patient is treated with the same antibiotic. The reasoning for this remains largely elusive. Antibiotic susceptibility to four antibiotics (ceftazidime, meropenem, minocycline and trimethoprim-sulfamethoxazole) was determined in consecutive isolates ( n = 11) from an adult cystic fibrosis patient, over a 63 month period. Each isolate displayed its own unique resistotype. The first isolate was sensitive to all four antibiotics, in accordance with Clinical and Laboratory Standards Institute methodology and interpretative criteria. Resistance was first detected at four months, showing resistance to ceftazidime and meropenen and intermediate resistance to minocycline and trimethoprim-sulfamethoxazole. Pan resistance was first detected at 18 months (resistotype IV), with three resistotypes (I, II and III) preceding this complete resistotype. The bacterium continued to display further antibiotic susceptibility heterogeneity for the next 45 months, with the description of an additional seven resistotypes (resistotypes V-XI). The Relative Resistance Index of this bacterium over the 63 month period showed no relationship between the development of antibiotic resistance and time. Adoption of mathematical modelling employing multinomial distribution demonstrated that large numbers of individual colony picks (>40/sputum), would be required to be 78% confident of capturing all 11 resistotypes present. Such a requirement for large numbers of colony picks combined with antibiotic susceptibility-related methodological problems creates a conundrum in biomedical science practice, in providing a robust assay that will capture antibiotic susceptibility variation, be pragmatic and cost-effective to deliver as a pathology service, but have the reliability to help clinicians select appropriate antibiotics for their patients. This study represents an advance in biomedical science as it demonstrates potential variability in antibiotic susceptibility testing with Burkholderia cenocepacia . Respiratory physicians and paediatricians need to be made aware of such variation by biomedical scientists at the bench, so that clinicians can contextualise the significance of the reported susceptibility result, when selecting appropriate antibiotics for their cystic fibrosis patient. Furthermore, consideration needs to be given in providing additional guidance on the laboratory report to highlight this heterogeneity to emphasise the potential for misalignment between susceptibility result and clinical outcome., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Moore, McCaughan, Rendall and Millar.)

Antimicrobial resistance (AMR) has now emerged as a chronic public health problem globally, with the forecast of 10 million deaths per year globally by 2050. AMR occurs when viruses, bacteria, fungi and parasites do not respond to antimicrobial treatments in humans and animals, thus allowing the survival of the microorganism within the host. The prominent cause contributing to the current crisis remains to be the overuse and misuse of antimicrobials, particularly the inappropriate usage of antibiotics, increasing the global burden of antimicrobial resistance. The global consumption and usage of antibiotics are therefore closely monitored at all times. This review provides a current overview of the implications of strategies used by international governmental organisations, including the UN's 17 Sustainable Development Goals (SDGs), to address the problem of antibiotic resistance, as well as the " One Health Approach ," a system incorporating a multidisciplinary effort to achieve the best possible health outcome by acknowledging the clear connections between humans, animals and their shared environment. The importance of public awareness and health literacy of lay audiences still needs to be further emphasised as part of global and local action plans. Antimicrobial resistance continues to be a major global public health dilemma of the 21st century. Already this topic is receiving substantial political input from the G7 countries and continues to be on the agenda of numerous political conferences. The consequences of failure to adequately address AMR are profound, with estimations of a return to the pre-antibiotic era, where everyday infections relating to childbirth, surgery and open fractured limbs could be potentially life-threatening. AMR itself represents a microcosm of factors, including social anthropology, civil unrest/war, diasporas, ethnic displacement, political systems, healthcare, economics, societal behaviour both at a population and individual level, health literacy, geoclimatic events, global travel and pharmaceutical innovation and investment, thus finding a solution that adequately addresses AMR and which helps stem further AMR emergence is complicated. Success will involve individuals, communities and nations all working together to ensure that the world continues to possess a sufficient armamentarium of effective antimicrobials that will sustain human and animal health, both now and in the future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Tang, Millar and Moore.)

Minimum inhibitory concentration to delafloxacin and ciprofloxacin were performed with Y. enterocolitica, Y. frederiksenii and Y. kristensenii. All organisms were sensitive to delafloxacin and ciprofloxacin. Our study indicates that delafloxacin may have a reasonable in vitro susceptibility profile against Yersinia among the species studied, which has not been previously reported., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: To better understand barriers and facilitators that contribute to antibiotic overuse in long-term care and to use this information to inform an evidence and theory-informed program., Methods: Information on barriers and facilitators associated with the assessment and management of urinary tract infections were identified from a mixed-methods survey and from focus groups with stakeholders working in long-term care. Each barrier or facilitator was mapped to corresponding determinants of behavior change, as described by the theoretical domains framework (TDF). The Rx for Change database was used to identify strategies to address the key determinants of behavior change., Results: In total, 19 distinct barriers and facilitators were mapped to 8 domains from the TDF: knowledge, skills, environmental context and resources, professional role or identity, beliefs about consequences, social influences, emotions, and reinforcements. The assessment of barriers and facilitators informed the need for a multifaceted approach with the inclusion of strategies (1) to establish buy-in for the changes; (2) to align organizational policies and procedures; (3) to provide education and ongoing coaching support to staff; (4) to provide information and education to residents and families; (5) to establish process surveillance with feedback to staff; and (6) to deliver reminders., Conclusions: The use of a stepped approach was valuable to ensure that locally relevant barriers and facilitators to practice change were addressed in the development of a regional program to help long-term care facilities minimize antibiotic prescribing for asymptomatic bacteriuria. This stepped approach provides considerable opportunity to advance the design and impact of antimicrobial stewardship programs.

Background: Antimicrobial resistance (AMR) has now emerged as a global public health crisis. Of particular concern is AMR associated with the genus Mycobacterium, including Mycobacterium tuberculosis and the nontuberculous mycobacteria (NTM). Emergence of the NTM, in particular Mycobacterium abscessus, in patients with cystic fibrosis (CF) represents both a diagnostic and a treatment dilemma. Such resistance drives the need to investigate novel sources of antimicrobials. Medicinal fungi have a well-documented history of use in traditional oriental therapies. Not only is this an ancient practice, but also still today, medical practice in Japan, China, Korea, and other Asian countries continue to rely on fungal-derived antibiotics. A study was, therefore, undertaken to examine the antimicrobial activity of 23 native macrofungal (mushrooms/toadstools) taxa, collected from woodlands in Northern Ireland against six clinical (CF) isolates of M. abscessus, as well as M. abscessus National Collection of Type Cultures (NCTC) Reference strain (NCTC 13031)., Methods: Free-growing saprophytic and mycorrhizal macrofungi (n = 23) belonging to the phylum Basidiomycota were collected and were definitively identified employing Polymerase Chain reaction/ITS DNA sequencing. Macrofungal tissues were freeze-dried and reconstituted before employment in antibiotic susceptibility studies., Results: All macrofungi examined showed varying inhibition of the M. abscessus isolates examined with the exception Russula nigricans. The macrofungi displaying maximum antimycobacterial activity against the clinical isolates were (in descending order) M. giganteus (33.6 mg/ml), Hygrocybe nigrescens (38.5 mg/ml) and Hypholoma fasciculare (25.3 mg/ml)., Conclusion: Macrofungi may represent a source of novel antimicrobials against M. abscessus, which have not yet been fully explored nor exploited clinically. This is the first report describing the antimycobacterial properties of extracts of M. giganteus against M. abscessus. Further work is now required to identify the constituents and mode of the inhibitory action of these macrofungi against the M. abscessus. Given the gravity of AMR in the NTMs, particularly M. abscessus and the clinical treatment dilemmas that such AMR present, antibiotic drug discovery efforts should now focus on investigating and developing antibacterial compounds from macrofungi, particularly M. giganteus, where there are no or limited current treatment options., Competing Interests: None

What Is Known and Objective: Ivacaftor is a novel potentiator of defective cystic fibrosis transmembrane conductance regulator (CFTR) protein, which corrects the gating defect and increases ion-function of activated cell-surface CFTR. Bacteria also regulate their physiology through ion channels. However, little is known about the potential effects of ivacaftor on bacterial ion channels, which, in turn, may have a potential effect on transport across the bacterial cell membrane. Therefore, any change in the ability to transport molecules across cell membranes in bacteria could have an important impact on bacterial transport physiology. One area where this could be particularly important is in the movement of antibiotics, both into and out of the bacterial cell. An in vitro study was therefore performed to examine the influence of ivacaftor at therapeutic concentration on antibiotic susceptibility of 11 commonly used anti-pseudomonal antibiotics against a population of clinical Pseudomonas aeruginosa [PA], from CF and non-CF sources., Method: Pseudomonas aeruginosa (n = 80; including 70 ivacaftor-naïve clinical PA from sputa from adult CF patients and 10 control PA from non-CF clinical blood culture sources) were examined. Antibiotic susceptibility was determined by standard disc diffusion assay using CLSI criteria and measuring zone size (mm), against four classes of anti-pseudomonal antibiotics, including beta-lactams (temocillin, ceftazidime, piperacillin/tazobactam, imipenem, meropenem and aztreonam), aminoglycosides (gentamicin, tobramycin, amikacin), fluoroquinolone (ciprofloxacin) and polymyxin (colistin), in the absence and presence of ivacaftor (5 μmol/L), as previously determined. In addition, all CF and non-CF PA were examined phenotypically in vitro, as previously described, for changes linked to bacterial virulence, including (i) growth density (ii) pigmentation, (iii) presence of adhesins and (iv) change to mucoidy, in the presence/absence of ivacaftor at therapeutic concentration., Results and Discussion: Antibiotic susceptibility did not decrease significantly with any of the antibiotics examined with CF PA isolates or with non-CF PA control organisms. There was a statistically significant increase in zone size (CF PA and amikacin, gentamicin, temocillin and ciprofloxacin; Non-CF PA and amikacin, gentamicin and aztreonam). However, at a population level, this did not translate into a shift in CLSI category to a more susceptible phenotype. None of the PA isolates examined were susceptible to ivacaftor alone, and additionally, no changes were noted with the four phenotypic parameters examined in the presence of ivacaftor., What Is New and Conclusion: This study showed that antibiotic susceptibility of commonly used anti-pseudomonal antibiotics was not negatively affected by ivacaftor, in a population of ivacaftor-naive P. aeruginosa., (© 2018 John Wiley & Sons Ltd.)

Background: Antimicrobial resistance (AMR) has rendered certain species of Mycobacterium difficult to treat clinically, particularly the nontuberculous Mycobacterium, Mycobacterium abscessus, in patients with cystic fibrosis (CF). Such patients are treated with several nonantibiotic medicines, which may have antimicrobial properties. Given the growing burden of AMR in M. abscessus, it is importtant to investigate the antimicrobial activity of all medicines used in the treatment of such patients. It was, therefore, the aim of this study to examine the antimicrobial activity of 10 nonantibiotic medicines used commonly in the treatment of CF., Methods: Antibiotic susceptibility studies were performed on human clinical isolates of M. abscessus (n = 16) including 11 smooth isolates, four rough isolates and one Reference isolate (NCTC 13031), against the following 10 nonantibiotic medicines:-aspirin (850 ug/ml), chlorphenamine (400 ug/ml), Creon (4000 international units/ml), cyclizine (50 mg/ml), DNase (1 μg/ml), hypertonic saline (NaCl) 7% (w/v), ibuprofen (44.4 mg/ml), lansoprazole (300 ug/ml), paracetamol (10 mg/ml), and prednisolone (500 ug/ml)., Results: Of the 10 nonantibiotic drugs investigated, inhibition of M. abscessus was noted with chlorphenamine (400 ug/ml), cyclizine (50 mg/ml), ibuprofen (44.4 mg/ml) and lansoprazole (300 ug/ml), with no activity associated with aspirin (850 ug/ml), Creon (4000 international units/ml), DNase (1 μg/ml), hypertonic saline (NaCl) 7% (w/v), paracetamol (10 mg/ml), and prednisolone (500 ug/ml). The minimum inhibitory concentration (MIC) of cyclizine to M. abscessus (n = 6) ranged from 8.0 to 12.5 ug/ml, with a mean MIC, MIC 50 , and MIC 90 of 10.6, 10.0 and 12.5 ug/ml, respectively., Conclusion: This study identified that chlorphenamine, cyclizine, ibuprofen, and lansoprazole have in vitro antimycobacterial activity against clinical M. abscessus, isolated from patients with CF. Further studies should now examine potential antimicrobial synergy between these compounds and common conventional antimycobacterial antibiotics, including the macrolides and fluoroquinolones, to decide how best to exploit such positive interactions to reduce AMR burden and improve treatment regimens., Competing Interests: None

Infection is a common complication of cystic fibrosis (CF) airway disease. Current treatment approaches include early intervention with the intent to eradicate pathogens in the hope of delaying the development of chronic infection and the chronic use of aerosolized antibiotics to suppress infection. The use of molecules that help restore CFTR (cystic fibrosis transmembrane conductance regulator) function, modulate pulmonary inflammation, or improve pulmonary clearance may also influence the microbial communities in the airways. As the pipeline of these new entities continues to expand, it is important to define when key pathogens are eradicated from the lungs of CF patients and, equally important, when new pathogens might emerge as a result of these novel therapies., (Copyright © 2018 American Society for Microbiology.)

Background: Antimicrobial resistance has rendered certain species of Mycobacterium difficult to treat clinically, particularly the nontuberculous Mycobacterium and Mycobacterium abscessus. While veterinary medicine and human medicine share many classes of antibiotics, there are several antibiotics which are uniquely licensed to veterinary medicine but not human medicine. It was, therefore, the aim of this study to examine the action of eight veterinary antibiotics to a population of multi- and pan-resistant M. abscessus, isolated from the sputum of patients with cystic fibrosis (CF)., Methods: Antibiotic susceptibility studies were performed on human clinical isolates of M. abscessus (n = 16), including 11 smooth isolates, 4 rough isolates, and 1 reference isolate (NCTC 13031), against the following 7 veterinary antibiotics (antibiotic class): apramycin (aminoglycoside), cefovecin (cephalosporin), ceftiofur (cephalosporin), framycetin (aminoglycoside), lincomycin (lincosamide), pirlimycin (lincosamide), and spectinomycin (aminocyclitol)., Results: M. abscessus isolates were sensitive (100%) to apramycin and framycetin but resistant (100%) to cefovecin, ceftiofur, lincomycin, pirlimycin, and spectinomycin., Conclusion: This study identified that the veterinary aminoglycosides, apramycin, and framycetin, have in vitro activity against multi-resistant clinical isolates of M. abscessus. Further studies should now compare the activity of these antibiotics against amikacin and the human aminoglycoside, advocated in the treatment of disease in CF patients, to determine if these novel antibiotics have a future role for the development in human medicine with such chronic disease patients., Competing Interests: There are no conflicts of interest

Background: Antimicrobial resistance (AMR) has rendered certain species of Mycobacterium difficult to treat clinically, particularly, the nontuberculous Mycobacterium, Mycobacterium abscessus. This bacterium is emerging in specific disease populations, including amongst cystic fibrosis (CF) patients, where AMR represent a true treatment dilemma. Therefore, any innovation with traditional antimicrobial compounds in spices, which increases the potency of existing conventional antibiotics should be investigated., Methods: M. abscessus isolates (n = 9 multidrug-resistant clinical isolates from CF patients + 1 Reference Strain) were examined for their direct susceptibility to 27 spices, as well as the interactive effect of this spice combination to their susceptibility to amikacin and linezolid antibiotic, with standard disk diffusion assay., Results: Five isolates of M. abscessus (5/10; 50%) failed to grow on the spice enriched medium, which included four clinical isolates and the National Culture Type Collection (NCTC) Reference Strain. Of the remaining five isolates which grew on the spice medium, no cultural phenotypic differences were observed, compared to unsupplemented controls. In the case of both amikacin and linezolid, the zone of inhibition increased with the inclusion of the spices. Initially, all isolates of M. abscessus were fully resistant to linezolid (mean zone of inhibition = 0 mm), and growth was to the edge of the antibiotic disk, whereas when in the presence of spices, large zones of inhibition were observed (mean zone of inhibition = 33.3 mm). With amikacin, the mean zone of inhibition increased from 23.2 mm to 32.0 mm, in the presence of spices., Conclusion: These data suggest that the spices were interacting synergistically with the antibiotics, thus making the antibiotic more potent against the bacteria tested. This study is significant as it demonstrates a positive interaction between spices and the conventional antimycobacterial antibiotics, amikacin, and linezolid. Given the burden of AMR to M. abscessus, particularly in a patient with chronic disease such as CF, any food-related innovation that can help maximize the potency of existing antimycobacterial antibiotics is to be encouraged and developed. The specific mechanism as to how spices increase the potency of such antibiotics with M. abscessus needs to be elucidated, as well as novel food (spice) delivery modalities developed, including novel medicinal foodstuffs or functional foods, that can harness this beneficial effect in vivo to medicine and society., Competing Interests: There are no conflicts of interest

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.)

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.)

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.

The aim of the present study was to assess the antimicrobial activity of methanol and ethanol extracts of pot marigold (Calendula officinalis) petals against clinical pathogens. The antimicrobial potential of C. officinalis extracts was evaluated against a panel of microorganisms isolated from patients at the Belfast City Hospital (BCH), including bacteria and fungi, using disc diffusion assay. Methanol extract of C. officinalis exhibited better antibacterial activity against most of the bacteria tested, than ethanol extract. Both methanol and ethanol extracts showed excellent antifungal activity against tested strains of fungi, while comparing with Fluconazole., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

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.)

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.

The aim of this study was to investigate the reliability of disc diffusion testing with penicillin, erythromycin and ciprofloxacin within the viridans group streptococci (VGS). In total, the antibiotic susceptibilities of 167 VGS isolates were compared by standard disc diffusion and broth microdilution methods, and these phenotypic data were compared to the carriage of the respective gene resistance determinants [ermB and mefA/E (macrolides); QRDR, gyrA, gyrB, parC and parE (quinolones)]. Overall, there were 35 discrepancies [resistant by MIC and susceptible by zone diameter (21.0%)] between MIC and disc diameter when penicillin susceptibility was interpreted by Clinical and Laboratory Standards Institute criteria. Scattergrams showed a bimodal distribution between non-susceptible and susceptible strains when erythromycin susceptibility was tested by both methods. Thirty-four (20.4%) isolates were categorized as resistant by MIC breakpoints, while disc diameter defined these as having intermediate resistance. With ciprofloxacin, three isolates (1.8%) showed minor discrepancies between MIC breakpoints and disc diameter. Isolates non-susceptible to all three antimicrobial agents tested were reliably distinguished from susceptible isolates by disc diffusion testing, except for the detection of low-level resistance to penicillin, where broth microdilution or an alternative quantitative MIC method should be used. Otherwise, we conclude that disc diffusion testing is a reliable method to detect strains of VGS non-susceptible to penicillin, erythromycin and ciprofloxacin, as demonstrated with their concordance to their gene resistance characteristics., (© 2011 SGM)

Objectives: Ciprofloxacin is the most frequently used member of the fluoroquinolones during initial eradication therapy of Pseudomonas aeruginosa, as well as during acute pulmonary exacerbations. However, its long-term effect on the susceptibility of the commensal flora within the cystic fibrosis (CF) airways has not yet been examined. The aim of this study was therefore to examine the consequence of oral ciprofloxacin usage on the resistance of the commensal viridans group streptococci (VGS), in terms of MICs and mutational analysis of the quinolone resistance-determining regions (QRDRs)., Methods: The MICs of ciprofloxacin, efflux activities and amino acid substitutions in the QRDRs for 190 isolates of VGS, originating from the sputa of adult CF patients who had been exposed constantly to ciprofloxacin, were examined. VGS organisms included Streptococcus salivarius, Streptococcus mitis, Streptococcus sanguinis, Streptococcus oralis, Streptococcus parasanguinis, Streptococcus infantis, Streptococcus gordonii, Streptococcus anginosus, Streptococcus cristatus, Streptococcus australis and Streptococcus mutans. Ciprofloxacin susceptibility was determined by broth microdilution and QRDRs within the gyrA, gyrB, parC and parE gene loci were explored using sequence analysis., Results: Twenty-seven (14.2%) streptococcal isolates were resistant to ciprofloxacin (MICs ≥8 mg/L) and 21 (11.1%) had reduced susceptibility (MICs 4 mg/L). As a comparator, clinically non-significant and non-invasive VGS organisms were examined in 12 consecutive non-CF patients in the community, where no resistance to ciprofloxacin was observed. Five novel QRDR PCR assays were developed to elucidate mutations within the CF VGS population, where there were six positions, which corresponded to previously reported quinolone resistance responsible mutations, and eight novel potential QRDR resistance mutations. Double mutations in gyrA and parC/parE led to MICs of 16 to >64 mg/L, while single mutations in parC or parE resulted in MICs of 8-32 mg/L and 8 mg/L, respectively. The mean homologies of each species to Streptococcus pneumoniae R6 were: gyrA, 70.3%-95%; gyrB, 69.6%-96.2%; parC, 76.1%-94.8%; and parE, 70.7%-94.7%. The close relatives of S. pneumoniae, S. mitis and S. oralis, showed high similarity for all four genes (more than 86%)., Conclusions: Treatment of P. aeruginosa with oral ciprofloxacin in patients with CF may concurrently reduce antibiotic susceptibility in the commensal VGS flora, where these organisms may potentially act as a reservoir of fluoroquinolone resistance gene determinants for newly acquired and antibiotic-susceptible pathogens, particularly the Streptococcus milleri group.

Methods employed by the World Health Organization (WHO) are used during this study to determine the optimum storage conditions for maintaining the culturability of Streptococcus pneumoniae in skimmed milk, tryptone, glucose and glycerin (STGG) transport medium. A comparison of S. pneumoniae strains sensitive and resistant to penicillin showed no significant difference in their survival ability in STGG medium. Furthermore, it is confirmed that storage at -70 degrees C remains most effective for maintaining viability by culture of S. pneumoniae. Storage at -20 degrees C would only be acceptable in the short-term, while storage at +4 degrees C is not recommended. Of note, this study has shown STGG medium at room temperature to be an efficient growth medium for pneumococci in the short-term. This work will help to establish robust sampling protocols when performing community studies to ensure culturability of comparison between community and laboratory pneumococci survival.

Objectives: Although long-term use of azithromycin has shown a significant clinical improvement for patients with cystic fibrosis (CF), its long-term effect on the susceptibility of commensal flora within CF airways has not yet been examined. We therefore suggest that long-term use of azithromycin increases macrolide resistance in commensal streptococci., Methods: Erythromycin susceptibility in naturally colonizing viridans group streptococci (VGS) was characterized, as well as macrolide resistance gene determinants through sequence analysis, in pneumococci (n = 15) and VGS [n = 84; i.e. Streptococcus salivarius (n = 30), Streptococcus mitis (n = 17), Streptococcus sanguinis (n = 11), Streptococcus oralis (n = 10), Streptococcus parasanguinis (n = 6), Streptococcus gordonii (n = 3), Streptococcus infantis (n = 3), Streptococcus cristatus (n = 2), Streptococcus anginosus (n = 1) and Streptococcus australis (n = 1)] isolated from sputum from 24 adult CF patients, who were on oral azithromycin therapy for at least the previous 7 months., Results: Almost three-quarters of isolates (74; 74.7%) were resistant to erythromycin, whilst a further 15 (15.2%) had reduced susceptibility, leaving only 10 (10.1%) isolates susceptible to erythromycin. The majority (89.8%) were not susceptible to erythromycin, as demonstrated by possession of the erm(B) gene in 25/99 (25.3%), the mef(A) gene in 1/99 (1.0%), the mef(E) gene in 75/99 (75.8%) and both erm(B) and mef(E) genes simultaneously in 11/99 (11.1%). These results indicate that genotypic resistance for macrolides is common in VGS in adult CF patients, with efflux being over three times more frequent., Conclusions: Long-term treatment with azithromycin in CF patients may reduce antibiotic susceptibility in commensal VGS, where these organisms may potentially act as a reservoir of macrolide resistance determinants for newly acquired and antibiotic-susceptible pathogens.

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.

Traditional herbal cures and remedies have played an important historical role in the treatment of a variety of illnesses and diseases in Northern Ireland for the last three hundred years. Recently, these have been reviewed in the publication by Linda Ballard from the Ulster Folk and Transport Museum at Cultra, Co. Down, which details the variety of local plants used and for what purpose. From this publication and another related publication, we note the description of several plant species that consistently appear in traditional cures and remedies, particularly used to treat infections and infectious diseases. Unfortunately, although these plants have strong associations with the local historical evidence base, there are very limited and mainly no formal publications in the medical/scientific evidence base, examining their scientific background and clinical efficacy.

Aims: To investigate the effect of sub-lethal challenge with tea tree oil (TTO) on the antibiotic resistance profiles of staphylococci., Methods and Results: Isolates of methicillin-resistant/-sensitive Staphylococcus aureus (MRSA and MSSA) and coagulase-negative staphylococci (CONS) were habituated to sub-lethal concentrations of TTO (72 h). Following habituation, the minimum inhibitory concentrations (MIC) of antibiotics and TTO were determined. Habituated MRSA/MSSA cultures had higher (P < 0.05) MIC values than control cultures for the examined antibiotics. Habituated MRSA/MSSA cultures also displayed decreased susceptibility to TTO. Although the MIC of habituated MRSA/MSSA for the examined antibiotics reverted to control values after subsequent culture in the absence of TTO, the increased MIC against TTO were maintained. When compared with control cultures, habituated CoNS cultures had higher (P < 0.05) MIC values against three-fifths of the antibiotics examined; no changes in TTO MIC were observed., Conclusions: TTO habituation 'stress-hardens' MRSA and MSSA, evidenced by transient decreased antibiotic susceptibility and stable decreased TTO susceptibility. Although TTO habituation did not decrease susceptibility of CoNS to TTO, such cultures showed transient decreased antibiotic susceptibility., Significance and Impact of the Study: Application of TTO at sub-lethal concentrations may reduce the efficacy of topical antibiotics used with TTO in combination therapies.

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.

Over the last decade, a novel methicillin-resistant Staphylococcus aureus (MRSA) has emerged, primarily associated with healthy individuals within the community. This organism is distinct from healthcare-associated MRSA (HA-MRSA) in terms of epidemiology, microbiology and clinical manifestation and as such has been defined as community-associated MRSA (CA-MRSA). Given that S. aureus is a major aetiological agent of infective endocarditis (IE), particularly associated with the iv drug user population, reports of IE attributed to CA-MRSA are now emerging in the literature. The aims of this article are to (i) define and contrast CA-MRSA with HA-MRSA; (ii) review the published cases of CA-MRSA IE to date; and (iii) evaluate the current international recommendations for antibiotic prophylaxis and treatment regimens for IE in relation to CA-MRSA.

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.

Previous research shows that approximately half of the coagulase-negative staphylococci (CNS) isolated from patients in the intensive care unit (ICU) at Belfast City Hospital were resistant to methicillin. The presence of this relatively high proportion of methicillin-resistance genetic material gives rise to speculation that these organisms may act as potential reservoirs of methicillin-resistance genetic material to methicillin-sensitive Staphylococcus aureus (MSSA). Mechanisms of horizontal gene transfer from PBP2a-positive CNS to MSSA, potentially transforming MSSA to MRSA, aided by electroporation-type activities such as transcutaneous electrical nerve stimulation (TENS), should be considered. Methicillin-resistant CNS (MR-CNS) isolates are collected over a two-month period from a variety of clinical specimen types, particularly wound swabs. The species of all isolates are confirmed, as well as their resistance to oxacillin by standard disc diffusion assays. In addition, MSSA isolates are collected over the same period and confirmed as PBP2a-negative. Electroporation experiments are designed to mimic the time/voltage combinations used commonly in the clinical application of TENS. No transformed MRSA were isolated and all viable S. aureus cells remained susceptible to oxacillin and PBP2a-negative. Experiments using MSSA pre-exposed to sublethal concentrations of oxacillin (0.25 microg/mL) showed no evidence of methicillin gene transfer and the generation of an MRSA. The study showed no evidence of horizontal transfer of methicillin resistance genetic material from MR-CNS to MSSA. These data support the belief that TENS and the associated time/voltage combinations used do not increase conjugational transposons or facilitate horizontal gene transfer from MR-CNS to MSSA.

The antimicrobial resistance profiles of Campylobacter isolates recovered from a range of retail food samples (n=374) and humans (n=314) to eight antimicrobial compounds were investigated. High levels of resistance in food C. jejuni isolates were observed for ceftiofur (58%), ampicillin (25%) and nalidixic acid (17%) with lower levels observed for streptomycin (7.9%) and chloramphenicol (8.3%). A total of 80% of human C. jejuni isolates were resistant to ceftiofur, while 17% showed resistance to ampicillin and nalidixic acid, 8.6% to streptomycin and 4.1% to chloramphenicol. Resistance to clinically relevant antimicrobials such as erythromycin, ciprofloxacin and tetracycline was 6.7, 12, and 15% respectively for all food isolates and was similar to corresponding resistance prevalences observed for human isolates, where 6.4, 12 and 13% respectively were found to be resistant. Comparisons of C. jejuni isolates in each location showed a high degree of similarity although some regional variations did exist. Comparison of total C. jejuni and C. coli populations showed minor differences, with C. jejuni isolates more resistant to ampicillin and ceftiofur. Multidrug resistance patterns showed some profiles common to human and clinical isolates.

Antibiotic resistance, particularly with the fluoroquinolones and macrolide antibiotics, has now emerged globally with thermophilic campylobacters, including Campylobacter jejuni and C. coli, giving rise to concerns about how these organisms have acquired such resistance characteristics, as well as consequences for human and animal treatment. This review examines (i) the clinical epidemiology of antibiotic resistance in human and animal thermophilic campylobacters, (ii) an update on resistance rates globally, (iii) surveillance of antimicrobial resistance in campylobacters originating from animals, particularly poultry, (iv) the role of the environment in the acquisition and transmission of antibiotic-resistant campylobacters, as well as (v) issues of biocide resistance in campylobacters.

A simple microtitre plate assay is used to detect antimicrobial activity in clinical urine specimens and its potential as a screening tool is assessed. The assay is based on a colorimetric substrate, p-nitrophenyl-beta-D-glucopyranoside, in combination with a Bacillus subtilis strain to detect antimicrobial residues. The assay identified antimicrobial activity in 31% of the 527 clinical urine samples tested. The majority of the samples (65%) came from the community, with the rest comprising hospital inpatients (19%) and out-patients (16%). The results demonstrated that there is an association between gender and the presence of inhibitory substances, as 40% of males and 27% of females tested positive. Just over two-fifths of hospital patients (46%) tested positive for inhibitory substances, compared to 26% of samples from community patients. Of the 306 samples that were culture-negative (<10(4) bacteria/mL), 42% were positive for inhibitory substances, compared with 17% among the remaining 221 samples. However, there was no evidence of an association between age and the presence of inhibitory substances. This study demonstrates that the bacteriostatic effect of the bacterial preservative boric acid is sufficient to upset the specificity of the assay. Furthermore, it has been suggested that antimicrobial activity can confuse the interpretation of culture results, as they have been found to play a major role in the occurrence of apparently sterile pyuria.

Infective endocarditis (IE) is associated with a high degree of morbidity and mortality and generally presents in patients with altered and abnormal heart architecture combined with exposure to bacteria through trauma and other potentially high-risk activities, including body piercing. Modern social behaviour has resulted in increased popularity of the practice of body piercing, particularly amongst the adolescent population and there has been a marked rise of cases of IE directly attributable to this practice. In this article we wish to examine the aetiology of such cases reported in the literature, with particular emphasis on causal organism, as well as to discuss the role of antibiotic prophylaxis and awareness in such at-risk patients within the primary care community.