Two-Year Evaluation of Legionella in an Aging Residential Building: Assessment of Multiple Potable Water Remediation Approaches

Legionella is an opportunistic waterborne pathogen that is difficult to eradicate in colonized drinking water pipes. Legionella control is further challenged by aging water infrastructure and lack of evidence-based guidance for building treatment. This study assessed multiple premise water remediation approaches designed to reduce Legionella pneumophila (Lp) within a residential building located in an aging, urban drinking water system over a two-year period. Samples (n=745) were collected from hot and cold-water lines and quantified via most probable number culture. Building-level treatment approaches included three single heat shocks (HS), three single chemical shocks (CS), and continuous low-level chemical disinfection (CCD) in the potable water system. The building was highly colonized with Lp with 71% Lp positivity. Single HS had a statistically significant Lp reduction one day post treatment but no significant Lp reduction one, two, and four weeks post treatment. The first two CS resulted in statistically significant Lp reduction at two days and four weeks post treatment, but there was a significant Lp increase at four weeks following the third CS. CCD resulted in statistically significant Lp reduction ten weeks post treatment implementation. This demonstrates that in a building highly colonized with Lp, sustained remediation is best achieved using CCD.

A multi-centre retrospective study of Nocardia speciation and antimicrobial susceptibility in Queensland, Australia

The study aims to characterise the species identification and antimicrobial susceptibility testing (AST) results of Nocardial isolates from adult patients across major public hospitals in Queensland, Australia, over a 15-year period. A multi-centre retrospective observational study of Nocardia sp. isolates was conducted from 7 major public hospitals in Queensland, Australia, over a 15-year period. Clinical samples from patients aged ≥ 18 years that isolated Nocardia sp. were included. Demographic and clinical data were collected, along with species identification and AST results. Overall, 484 Nocardia sp. were isolated. Most patients were male (297, 61%) with a mean (IQR) age of 60 (51-75) and a median (IQR) Charlson Comorbidity Index of 4 (2-6). Of these, 239 (49%) patients were immunosuppressed. Organisms were most frequently isolated from sputum (174, 36%), and superficial swabs (102, 21%). Patients presented with pulmonary infections (165, 35%) and superficial skin and soft tissue infections (87, 18%) most commonly. One hundred (21%) isolates were deemed pulmonary colonisation and were not treated. Of the speciated organisms, N. nova complex was the most common (93, 19%), followed by N. farcinica complex (79, 16%). Organisms were reliably susceptible to linezolid (240/245, 98%), amikacin (455/470, 97%), and trimethoprim/sulfamethoxazole (459/476, 96%), but less so to imipenem (243/472, 51%) and ceftriaxone (261/448, 58%). This is the largest Australian description of Nocardia sp. to date. Given antimicrobials are often commenced prior to AST results and sometimes even speciation, characterisation of local species and antibiogram data is important to guide empiric choices and local guidelines.

Comparison of suspected and confirmed internal EVD-related infections: a prospective multi-centre U.K. observational study

Background

Diagnosis of internal external ventricular drain (EVD)-related infections (iERI) is an area of diagnostic difficulty. Empiric treatment is often initiated on clinical suspicion. There is limited guidance around antimicrobial management of confirmed versus suspected iERI.

Methods

Data on patients requiring EVD insertion were collected from 21 neurosurgical units in the United Kingdom from 2014 to 2015. Confirmed iERI was defined as clinical suspicion of infection with positive cerebrospinal fluid (CSF) culture and/or Gram stain. Cerebrospinal fluid, blood, and clinical parameters and antimicrobial management were compared between the 2 groups. Mortality and Modified Rankin Scores were compared at 30 days post-EVD insertion.

Results

Internal EVD-related infection was suspected after 46 of 495 EVD insertions (9.3%), more common after an emergency insertion. Twenty-six of 46 were confirmed iERIs, mostly due to Staphylococci (16 of 26). When confirmed and suspected infections were compared, there were no differences in CSF white cell counts or glucose concentrations, nor peripheral blood white cell counts or C-reactive protein concentrations. The incidence of fever, meningism, and seizures was also similar, although altered consciousness was more common in people with confirmed iERI. Broad-spectrum antimicrobial usage was prevalent in both groups with no difference in median duration of therapy (10 days [interquartile range {IQR}, 7–24.5] for confirmed cases and 9.5 days [IQR, 5.75–14] for suspected, P = 0.3). Despite comparable baseline characteristics, suspected iERI was associated with lower mortality and better neurological outcomes.

Conclusions

Suspected iERI could represent sterile inflammation or lower bacterial load leading to false-negative cultures. There is a need for improved microbiology diagnostics and biomarkers of bacterial infection to permit accurate discrimination and improve antimicrobial stewardship.

Optimizing Human Intestinal Enteroids for Environmental Monitoring of Human Norovirus

Human noroviruses (HuNoV) are the leading cause of gastrointestinal illness and environmental monitoring is crucial to prevent HuNoV outbreaks. The recent development of a HuNoV cell culture assay in human intestinal enteroids (HIEs) has enabled detection of infectious HuNoV. However, this complex approach requires adaptation of HIEs to facilitate HuNoV replication from environmental matrixes. Integrating data from 200 experiments, we examined six variables: HIE age, HIE basement membrane compounds (BMC), HuNoV inoculum processing, HuNoV inoculum volume, treatment of data below limit of detection (LOD), and cutoff criteria for determining positive HuNoV growth. We infected HIEs with HuNoV GII.4 Sydney positive stool and determined 1.4 × 10³ genome equivalents per HIE well were required for HuNoV replication. HIE age had minimal effect on assay outcomes. LOD replacement and cutoff affected data interpretation, with lower values resulting in higher estimated HuNoV detection. Higher inoculum volumes lead to minimal decreases in HuNoV growth, with an optimal volume of 250uL facilitating capture of low concentrations of HuNoVs present in environmental isolates. Processing of HuNoV inoculum is valuable for disinfection studies and concentrating samples but is not necessary for all HIE applications. This work enhances the HuNoV HIE cell culture approach for environmental monitoring. Future HIE research should report cell age as days of growth and should clearly describe BMC choice, LOD handling, and positive cutoff.

Recovery of Infectious Human Norovirus GII.4 Sydney From Fomites via Replication in Human Intestinal Enteroids

Contamination of fomites by human norovirus (HuNoV) can initiate and prolong outbreaks. Fomite swabbing is necessary to predict HuNoV exposure and target interventions. Historically, swab recovered HuNoV has been measured by molecular methods that detect viral RNA but not infectious HuNoV. The recent development of HuNoV cultivation in human intestinal enteroids (HIEs) enables detection of infectious HuNoV. It is unknown if the swabbing process and swab matrix will allow for cultivation of fomite recovered HuNoV. We used HIEs to culture swab-recovered HuNoV GII.4 Sydney from experimentally infected surfaces—a hospital bed tray (N = 32), door handle (N = 10), and sanitizer dispenser (N = 11). Each surface was swabbed with macrofoam swabs premoistened in PBS plus 0.02% Tween80. Swab eluate was tested for infectious HuNoV by cultivation in HIE monolayers. Infectious HuNoV can be recovered from surfaces inoculated with at least 10⁵ HuNoV genome equivalents/3 cm². In total, 57% (N = 53) of recovered swabs contained infectious HuNoV detected by HIEs. No difference in percent positive swabs was observed between the three surfaces at p = 0.2. We demonstrate that fomite swabbing can be combined with the HIE method to cultivate high titer infectious HuNoV from the environment, filling a significant gap in HuNoV detection. Currently, high titers of HuNoV are required to measure growth in HIEs and the HIE system precludes absolute quantification of infectious viruses. However, the HIE system can provide a binary indication of infectious HuNoV which enhances existing detection methods. Identification of infectious HuNoVs from swabs can increase monitoring accuracy, enhance risk estimates, and help prevent outbreaks.

Second surgery for progressive glioblastoma: a multi-centre questionnaire and cohort-based review of clinical decision-making and patient outcomes in current practice

PURPOSE

Glioblastoma prognosis is poor. Treatment options are limited at progression. Surgery may benefit, but no quality guidelines exist to inform patient selection. We sought to describe variations in surgical management at progression, highlight where further evidence is needed, and build towards a consensus strategy.

METHODS

Current practice in selection of patients with progressive GBM for second surgery was surveyed online amongst specialists in the UK and Europe. We complemented this with an assessment of practice in a retrospective cohort study from six United Kingdom neurosurgical units. We used descriptive statistics to analyse the data.

RESULTS

234 questionnaire responses were received. Maintaining or improving patient quality of life was key to decision making, with variation as to whether patient age, performance status or intended extent of resection was relevant. MGMT methylation status was not important. Half considered no minimum time after first surgery. 288 patients were reported in the cohort analysis. Median time to second surgery from first surgery 390 days. Median overall survival 815 days, with no association between time to second surgery and time to death (p = 0.874).

CONCLUSIONS

This is the most wide-ranging examination of contemporaneous practice in management of GBM progression. Without evidence-based guidelines, the variation is unsurprising. We propose consensus guidelines for consideration, to reduce heterogeneity in decision making, support data collection and analysis of factors influencing outcomes, and to inform clinical trials to establish whether second surgery improves patient outcomes, or simply selects to patients already performing well.

Drug-resistant tuberculosis diagnosis since Xpert® MTB/RIF introduction in Papua New Guinea, 2012-2017

SETTING

Xpert® MTB/RIF was introduced in Papua New Guinea in 2012 for the diagnosis of tuberculosis (TB) and of rifampicin-resistant TB (RR-TB), a marker of multi-drug-resistant TB (MDR-TB).

OBJECTIVE

To assess the concordance of Xpert with phenotypic drug susceptibility testing (DST) performed at the supranational reference laboratory and to describe the patterns of drug-resistant TB observed.

DESIGN

This was a retrospective descriptive study of laboratory data collected from April 2012 to December 2017.

RESULTS

In 69 months, 1408 specimens with Xpert results were sent for mycobacterial culture and DST; Mycobacterium tuberculosis was cultured from 63% (884/1408) and DST was completed in 99.4%. The concordance between Xpert and culture for M. tuberculosis detection was 98.6%. Of 760 RR-TB cases, 98.7% were detected using Xpert; 98.5% of 620 MDR-TB cases were identified using phenotypic DST. Phenotypic resistance to second-line drugs was detected in 59.4% (522/879) of specimens tested, including 29 with fluoroquinolone resistance; the majority were from the National Capital District and Daru Island.

CONCLUSION

The high concordance between phenotypic DST and Xpert in identifying RR-TB cases supports the scale-up of initial Xpert testing in settings with high rates of drug resistance. However, rapid DST in addition to the detection of RR-TB is required.

Multidrug-resistant tuberculosis in Australia, 1998-2012

OBJECTIVE

To describe the epidemiology and outcomes of multidrug-resistant tuberculosis (MDR-TB) diagnosed in Australia between 1998 and 2012.

DESIGN

A retrospective review was undertaken involving all patients with laboratory-confirmed MDR-TB notified in Australia between 1998 and 2012 inclusive. Demographic, clinical and laboratory features are described. Clinical outcomes were defined according to World Health Organization definitions of treatment success (cure and treatment completion), treatment failure, death, loss to follow-up (including transfer out), or not evaluated at treatment completion.

RESULTS

A total of 244 cases of MDR-TB were diagnosed in Australia during the study period, representing 1.4% of all TB cases notified. The majority were born outside Australia, including one third in Papua New Guinea. Of those with treatment outcome data available, treatment success was demonstrated in 81%. Treatment success was positively associated with use of a second-line injectable agent. Those born in Papua New Guinea were less likely to achieve treatment success.

CONCLUSION

MDR-TB is uncommon in Australia. The large number of cases born in Papua New Guinea, and the poorer outcomes in this cohort, represent challenges with cross-border management of MDR-TB in the Torres Strait. Australia has an ongoing role in the prevention and management of MDR-TB locally and in the region.

Multidrug-resistant tuberculosis in Queensland, Australia: an ongoing cross-border challenge

SETTINGp: Multidrug-resistant tuberculosis (MDR-TB) is a growing concern worldwide. In Australia, although the incidence of MDR-TB remains low, Queensland is at an increased risk due to its proximity to Papua New Guinea (PNG).

OBJECTIVE

To examine the epidemiology, clinical features and outcomes of MDR-TB in Queensland, with a comparison between cross-border PNG and non-cross-border patients.

DESIGN

Retrospective case series of all MDR-TB patients in Queensland between 1 January 2000 and 31 December 2014.

RESULTS

Ninety-six patients were diagnosed with MDR-TB in Queensland between 2000 and 2014. The majority were cross-border PNG nationals diagnosed within the Torres Straight Protected Zone (n = 73, 76%). Cross-border patients were younger (27.4 vs. 36.3 years, P = 0.02), had spent less time in Australia before diagnosis (<1 vs. 19 months, P < 0.01), had higher rates of smear positivity (67.1% vs. 40%, P = 0.04) and were less likely to have received a second-line injectable agent (45.8% vs. 71.4%, P = 0.05). Cross-border patients had significantly lower rates of treatment success than non-cross-border patients (47.9% vs. 85.7%; P < 0.01).

CONCLUSION

MDR-TB cases in Queensland are largely a result of cross-border PNG nationals, with poorer outcomes seen in this cohort. Continued strengthening of the region's TB programmes, with a focus on cross-border patients, is required.

Effects of pH Variability on Peracetic Acid Reduction of Human Norovirus GI, GII RNA, and Infectivity Plus RNA Reduction of Selected Surrogates

With increasing interest in peracetic acid (PAA) as a disinfectant in water treatment processes, this study determined PAA treatment effects on human noroviruses (hNoVs) genotype I (GI) and genotype II (GII) as well as effects on bacteriophage MS2 and murine norovirus (MNV) in relation to pH. Across all pH conditions, PAA achieved between 0.2 and 2.5 log₁₀ reduction of hNoVs over 120 min contact time in buffer solution as measured by reverse transcription-qPCR (RT-qPCR). The PAA treatments produced similar RT-qPCR reductions of MS2 and MNV, in the range of 0.2-2.7 log₁₀. Infectivity assays achieved > 4 log₁₀ reduction of both MS2 and MNV in buffer solution after 120 min contact time. Comparing PAA activity across varying pH, disinfection at pH 8.5, in general, resulted in less reduction of infectivity and molecular signals compared to pH conditions of 6.5 and 7.5. This difference was most pronounced for reductions in infectivity of MNV and MS2, with as much as 2.7 log₁₀ less reduction at pH 8.5 relative to lower pH conditions. This study revealed that PAA was an effective disinfectant for treatment of hNoV GI and GII, MS2 and MNV, with greatest virus reduction observed for MS2 and MNV infectivity. RT-qPCR reductions of MS2 and MNV were lower than concurrent MS2 and MNV infectivity reductions, suggesting that observed hNoV RT-qPCR reductions may underestimate reductions in hNoV infectivity achieved by PAA. Although virus disinfection by PAA occurred at all evaluated pH levels, PAA is most effective at pH 6.5-7.5.

MOLECULAR TYPING OF MYCOBACTERIUM KANSASII — A GLOBAL PERSPECTIVE

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Responding to Mycobacterium chimaera heater-cooler unit contamination: international and national intersectoral collaboration coordinated in the state of Queensland, Australia

BACKGROUND

The index case of Mycobacterium chimaera infection in a patient following open cardiac surgery in the state of Queensland, Australia prompted a centralized coordinated response to mitigate the risk.

AIM

To describe the public health response to M. chimaera contamination of heater-cooler units (HCUs) and patient infection.

METHODS

A public health sector strategy was developed with national and international consultation to respond to the threat of HCUs contaminated with M. chimaera. Data linkage of non-tuberculous mycobacterium notifications and selected procedures was undertaken where potential use of HCUs was identified through hospitalization records. Water sampling and testing protocols were standardized. Public disclosure and patient notification were undertaken.

FINDINGS

A single case of disseminated M. chimaera infection in a patient has been diagnosed to date in Queensland, Australia. Ten of 12 (83%) LivaNova Stockert 3T HCUs from five hospitals tested positive for M. chimaera. In total, 5650 patients were notified by post of their potential risk of exposure. Use of the telehealth call centre was modest. M. chimaera was also found in extracorporeal membrane oxygenation heater units produced by two other device manufacturers, four of which tested positive prior to commissioning for use.

CONCLUSIONS

Rapid international collaboration optimized the Queensland Health response to potential M. chimaera exposure during cardiac surgery. State-wide collaboration ensured a transparent, consistent approach to contacting patients and informing the public of the potential risk. A framework for ongoing risk management, clinical awareness and laboratory diagnosis was established. No further cases of M. chimaera infection have been identified in Queensland.

Paediatric tuberculosis in Queensland, Australia: overrepresentation of cross-border and Indigenous children

SETTING

Queensland, Australia.

BACKGROUND

Understanding paediatric tuberculosis (TB) is important, as children with TB typically reflect recent community transmission. Children pose unique diagnostic challenges and are at risk of developing severe disseminated infection.

OBJECTIVE

To describe the epidemiology, presentation and outcomes of children with TB disease in Queensland.

DESIGN

This is a retrospective case series of children diagnosed with TB aged 0-16 years notified in 2005-2014. Data collected in the Queensland Notifiable Conditions System were extracted and analysed.

RESULTS

Of 127 children diagnosed with TB, 16 were Australian-born (including 12 Indigenous Queenslanders), 41 were overseas-born permanent and temporary residents and 70 were cross-border Papua New Guinea (PNG) children; 88 children had pulmonary disease (with/without other sites) and 39 had extra-pulmonary disease only, with lymph node TB the predominant extra-pulmonary site; 70.1% of children had laboratory confirmation; and 14 cross-border children had multidrug-resistant TB. Treatment outcomes among children residing in Australia were good (100% among Australian-born and 97.2% among permanent and temporary residents), but they were less favourable among PNG children diagnosed in the Torres Strait Protected Zone (76.6%).

CONCLUSION

Queensland has unique challenges in TB control, with a high proportion of cross-border diagnoses and over-representation of Indigenous children. Vigilance is needed given the wide spectrum of clinical presentation, particularly in high-risk communities.

Epidemiological Analysis of Methicillin-ResistantStaphylococcus aureusIsolates From Adult Patients With Cystic Fibrosis

Using pulsed-field gel electrophoresis, we genotyped 21 methicillin-resistantStaphylococcus aureusisolates from patients attending an adult cystic fibrosis unit. Eleven patients exhibited pulsotypes related to 2 locally endemic strains. Eleven chronically colonized patients were assessed over a period of up to 2 years, and all demonstrated a retention of strain type.

Rifampicin-resistant Mycobacterium tuberculosis: susceptibility to isoniazid and other anti-tuberculosis drugs

Based on data from 14 Supranational Tuberculosis (TB) Reference Laboratories worldwide, the proportion of rifampicin (RMP) resistant isolates that were isoniazid (INH) susceptible by phenotypic drug susceptibility testing varied widely (0.5-11.6%). RMP-resistant isolates that were INH-susceptible had significantly lower rates of resistance to other first- and second-line anti-tuberculosis drugs (except rifabutin) compared to multidrug-resistant isolates. RMP resistance is not always a good proxy for a presumptive diagnosis of multidrug-resistant TB, which has implications for use of molecular assays that identify only RMP resistance-associated DNA mutations.

Genetic diversity of Mycobacterium tuberculosis in Madang, Papua New Guinea

SETTING

Madang and surroundings, Papua New Guinea (PNG).

OBJECTIVE

To characterise the genetic diversity and drug susceptibility of Mycobacterium tuberculosis isolates collected in Madang and surroundings.

DESIGN

M. tuberculosis was isolated from sputum samples from active pulmonary tuberculosis cases. Drug resistance profiles were obtained by drug susceptibility testing. M. tuberculosis lineages were identified by single nucleotide polymorphisms and sub-typing was performed by spoligotyping. Spoligotyping and 24 locus mycobacterial interspersed repetitive units-variable number of tandem repeats were combined to identify clustered isolates.

RESULTS

The 173 M. tuberculosis isolates collected belonged predominantly to the Euro-American lineage (Lineage 4) and the East-Asian lineage (Lineage 2). Multidrug-resistant M. tuberculosis were observed in 5.2% of isolates. Lineage 2 M. tuberculosis, which includes the 'Beijing' genotype, was significantly associated with any drug resistance (OR 5.2, 95%CI 1.8-15.1). Cluster analyses showed 44% molecularly clustered isolates, suggesting transmission of M. tuberculosis in the community, including transmission of primary drug-resistant M. tuberculosis.

CONCLUSION

These data provide the first insight into the molecular characteristics of M. tuberculosis in the Madang area of PNG, and indicate substantial drug resistance with evidence of ongoing transmission.

Resistance patterns of multidrug-resistant tuberculosis in Western Province, Papua New Guinea

Few data are available on tuberculosis (TB) drug resistance patterns in Papua New Guinea (PNG) due to the lack of facilities for mycobacterial culture. Many patients from the Western Province seek care in Queensland health clinics in the Torres Strait. Since 2000, we have treated 161 TB cases from PNG, of whom 40 proved to have multidrug-resistant TB (MDR-TB; two human immunodeficiency virus positive). Drug susceptibility testing (DST) shows high levels of resistance to other drugs in the MDR-TB cases (streptomycin 93%, ethionamide 87%, ethambutol 18%, pyrazinamide 10%). No extensively drug-resistant TB (XDR-TB) has been identified. MDR-TB seems to be highly prevalent in the Western Province of PNG, and unless treatment is guided by DST, the risk of XDR-TB emerging is high.

Purification and Properties of an S-Adenosylmethionine: 2,4-Disubstituted Phenol O-Methyltransferase from Phanerochaete chrysosporium

An enzyme catalyzing the O-methylation of acetovanillone (3-methoxy-4-hydroxyacetophenone) by S-adeno-sylmethionine was isolated from Phanerochaete chrysosporium and purified 270-fold by ultrafiltration, anion-exchange chromatography, and gel filtration. The enzyme exhibited a pH optimum between 7 and 9 and was rapidly denatured at temperatures above 55 degrees C. The K(m) values for acetovanillone and S-adenosylmethionine were 34 and 99 muM, respectively. S-Adenosylhomocysteine acted as a powerful competitive inhibitor of S-adenosylmethionine, with a K(i) of 41 muM. The enzyme was also susceptible to inhibition by thiol reagents and low concentrations of heavy metal ions. Gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the enzyme was monomeric and had a molecular weight of approximately 53,000. Substrate specificity studies showed that 3-methoxy- and 3,5-dimethoxy-substituted 4-hydroxy-benzaldehydes, -benzoic acids, and -acetophenones were the preferred substrates for the enzyme. The corresponding 3,4-dihydroxy compounds were methylated relatively slowly, while the 3-hydroxy-4-methoxy compounds were almost inactive as substrates. Substituents in both the 2 and 4 positions relative to the hydroxyl group appeared to be essential for significant enzyme attack of a substrate. Provided that certain steric criteria were satisfied, the nature of the substituent was not critical. Hence, xenobiotic compounds such as 2,4-dichlorophenol and 2,4-dibromophenol were methylated almost as readily as acetovanillone. However, an extended side chain in the 4 position was not compatible with activity as a substrate, and neither homovanillic, caffeic, nor ferulic acid was methylated. The substrate range of the O-methyltransferase tends to imply a role in the catabolism or detoxification of lignin degradation products such as vanillic and syringic acids.

Cough-generated aerosols of Pseudomonas aeruginosa and other Gram-negative bacteria from patients with cystic fibrosis

BACKGROUND

Pseudomonas aeruginosa is the most common bacterial pathogen in patients with cystic fibrosis (CF). Current infection control guidelines aim to prevent transmission via contact and respiratory droplet routes and do not consider the possibility of airborne transmission. It was hypothesised that subjects with CF produce viable respirable bacterial aerosols with coughing.

METHODS

A cross-sectional study was undertaken of 15 children and 13 adults with CF, 26 chronically infected with P aeruginosa. A cough aerosol sampling system enabled fractioning of respiratory particles of different sizes and culture of viable Gram-negative non-fermentative bacteria. Cough aerosols were collected during 5 min of voluntary coughing and during a sputum induction procedure when tolerated. Standardised quantitative culture and genotyping techniques were used.

RESULTS

P aeruginosa was isolated in cough aerosols of 25 subjects (89%), 22 of whom produced sputum samples. P aeruginosa from sputum and paired cough aerosols were indistinguishable by molecular typing. In four cases the same genotype was isolated from ambient room air. Approximately 70% of viable aerosols collected during voluntary coughing were of particles <or=3.3 microm aerodynamic diameter. P aeruginosa, Burkholderia cenocepacia, Stenotrophomonas maltophilia and Achromobacter xylosoxidans were cultivated from respiratory particles in this size range. Positive room air samples were associated with high total counts in cough aerosols (p = 0.003). The magnitude of cough aerosols was associated with higher forced expiratory volume in 1 s (r = 0.45, p = 0.02) and higher quantitative sputum culture results (r = 0.58, p = 0.008).

CONCLUSION

During coughing, patients with CF produce viable aerosols of P aeruginosa and other Gram-negative bacteria of respirable size range, suggesting the potential for airborne transmission.

Microbiology of infected arthroplasty: implications for empiric peri-operative antibiotics

PURPOSE

To classify the spectrum and antibiotic susceptibility of bacteria isolated from infected hip and knee arthroplasty specimens, and to recommend appropriate empiric peri-operative antibiotics.

METHODS

From January 1999 to August 2006, specimens from revision hip and knee arthroplasties (with or without suspected infection) were routinely collected for identifying possible organisms and their susceptibility patterns. During the period, 147 patients had positive specimens yielding 248 micro-organisms (from 195 tissue specimens, 43 fluid specimens, and 10 swabs). 140 isolates were from hips and 108 from knees.

RESULTS

Most isolates were Gram-positive; their distribution was similar in hip and knee specimens. Of the 248 micro-organisms isolated, Staphylococcus was the most common genus encountered (131, 53%), followed by Gram-negative isolates (24%). 88% of Gram-negative organisms were detected within 48 hours of inoculation and 94% of Gram-positive organisms within 96 hours. Overall, 46% of isolates were susceptible to cephalothin. Only 35% of coagulase-negative staphylococci were sensitive to cephalothin. No Gram-positive vancomycin resistance was encountered.

CONCLUSION

Empiric prophylactic antibiotics for revision hip and knee arthroplasties should include vancomycin to cover Gram-positive organisms and gentamicin for most Gram-negative bacteria.

Stability of Delta(9)-tetrahydrocannabinol (THC) in oral fluid using the Quantisal collection device

This article details the stability of Delta(9)-tetrahydrocannabinol (THC) in oral fluid during collection, extraction and storage. Oral fluid is being increasingly used as the specimen of choice for the detection of drug use in various applications. Studies to determine the extraction efficiency of THC from the collection buffer and stability under various laboratory storage conditions were carried out. THC was extracted from the collection pad and buffer with an average efficiency over 80% and was stable in Quantisal oral fluid extraction buffer when stored at refrigerated temperatures. Fluorescent lighting caused THC losses of over 50%, however the presence of the pad reduced the loss. In the dark, the loss of THC at room temperature was approximately 20% over 14 days. When stored with the serum separators in place, THC losses were significant. After 3 days, THC concentration was reduced by almost 30%, and after 14 days, 60% of the drug was lost and the losses were not concentration dependent.

MRSA eradication in a health care worker with cystic fibrosis; re-emergence or re-infection?

Methicillin-resistant Staphylocosis aureus (MRSA) is an emerging infection in patients with cystic fibrosis (CF). MRSA may be a management dilemma for healthcare workers (HCWs) with CF. Eradication of MRSA with long-term rifampicin and fusidic acid can be achieved in patients with CF. We describe a case of recurrent MRSA infection in a HCW with CF. Molecular typing of the MRSA isolates supported re-infection rather than re-emergence of an earlier MRSA infection. Infection control advice for HCWs with CF who acquire MRSA remains controversial.

Clonal strains of Pseudomonas aeruginosa in paediatric and adult cystic fibrosis units

Despite recent reports of clonal strains of Pseudomonas aeruginosa in cystic fibrosis (CF) units, the need for routine microbiological surveillance remains contentious. Sputum was collected prospectively from productive patients attending the regional paediatric and adult CF units in Brisbane, Australia. All P. aeruginosa isolates were typed using pulsed-field gel electrophoresis. Spirometry, anthropometrics, hospitalisations and antibiotic sensitivity data were recorded. The first 100 sputum samples (first 50 patients at each clinic) harboured 163 isolates of P. aeruginosa. A total of 39 patients shared a common strain (pulsotype 2), 20 patients shared a strain with at least one other patient and 41 patients harboured unique strains. Eight patients shared a strain identical to a previously reported Australian transmissible strain (pulsotype 1). Compared with the unique strain group, patients harbouring pulsotype 2 were younger and had poorer lung function. Treatment requirements were similar in these two groups, as were the rates of multiresistance. In conclusion, 59% of patients harboured a clonal strain, supporting the need for routine microbiological surveillance. In contrast to previously described clonal strains, the dominant pulsotype was indistinguishable from nonclonal strains with respect to both colonial morphology and multiresistance. The clinical significance of clonal strains remains uncertain and requires longitudinal study.

Rifampicin and sodium fusidate reduces the frequency of methicillin-resistant Staphylococcus aureus (MRSA) isolation in adults with cystic fibrosis and chronic MRSA infection

Nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA) to patients with cystic fibrosis (CF) frequently results in chronic respiratory tract carriage. This is an increasing problem, adds to the burden of glycopeptide antibiotic use in hospitals, and represents a relative contraindication to lung transplantation. The aim of this study was to determine whether it is possible to eradicate MRSA with prolonged oral combination antibiotics, and whether this treatment is associated with improved clinical status. Adult CF patients (six male, one female) with chronic MRSA infection were treated for six months with rifampicin and sodium fusidate. Outcome data were examined for six months before treatment, on treatment and after treatment. The patients had a mean age of 29.3 (standard deviation=6.3) years and FEV(1) of 36.1% (standard deviation=12.7) predicted. The mean duration of MRSA isolation was 31 months. MRSA isolates identified in these patients was of the same lineage as the known endemic strain at the hospital when assessed by pulsed-field gel electrophoresis. Five of the seven had no evidence of MRSA during and for at least six months after rifampicin and sodium fusidate. The proportion of sputum samples positive for MRSA was lower during the six months of treatment (0.13) and after treatment (0.19) compared with before treatment (0.85) (P<0.0001). There was a reduction in the number of days of intravenous antibiotics per six months with 20.3+/-17.6 on treatment compared with 50.7 before treatment and 33.0 after treatment (P=0.02). There was no change in lung function. Gastrointestinal side effects occurred in three, but led to therapy cessation in only one patient. Despite the use of antibiotics with anti-staphylococcal activity for treatment of respiratory exacerbation, MRSA infection persists. MRSA can be eradicated from the sputum of patients with CF and chronic MRSA carriage by using rifampicin and sodium fusidate for six months. This finding was associated with a significant reduction in the duration of intravenous antibiotic treatment during therapy.

Burkholderia pseudomallei: another emerging pathogen in cystic fibrosis

BACKGROUND

Burkholderia pseudomallei is an important cause of acute fulminant pneumonia and septicaemia in tropical regions of northern Australia and south east Asia. Subacute and chronic forms of the disease also occur. There have been three recent reports of adults with cystic fibrosis (CF) who presumably acquired B pseudomallei infection during extended vacations or residence in either Thailand or northern Australia.

METHODS

The clinical course, molecular characteristics, serology and response to treatment are described in four adult CF patients infected with B pseudomallei. Polymerase chain reaction (PCR) based methods were used to confirm B pseudomallei and exclude B cepacia complex. Genotyping was performed using randomly amplified polymorphic DNA (RAPD) PCR and pulsed field gel electrophoresis (PFGE).

RESULTS

Four patients are described with a mean duration of infection of 32 months. All but one patient lived in tropical Queensland. Two patients (with the longest duration of infection) deteriorated clinically and one subsequently died of respiratory failure. Both responded to intravenous treatment specifically targeting B pseudomallei. Another patient suffered two severe episodes of acute bronchopneumonia following acquisition of B pseudomallei. Eradication of the organism was not possible in any of the cases. PFGE of a sample isolate from each patient revealed the strains to be unique and RAPD analysis showed retention of the same strain within an individual over time.

CONCLUSIONS

These findings support a potential pathogenic role for B pseudomallei in CF lung disease, producing both chronic infection and possibly acute bronchopneumonia. Identical isolates are retained over time and are unique, consistent with likely environmental acquisition and not person to person spread. B pseudomallei is emerging as a significant pathogen for patients with CF residing and holidaying in the tropics.

Genomovar diversity amongst Burkholderia cepacia complex isolates from an Australian adult cystic fibrosis unit

In this study, a combination of recA-based PCR assays and 16S rDNA restriction fragment length polymorphism (RFLP) analysis was used to determine the genomovar diversity of clinical Burkholderia cepacia complex isolates. Twenty-eight isolates were prospectively collected from patients attending a large Australian adult cystic fibrosis (CF) unit, 22 isolates were referred from other Australian CF units and a further eight isolates originated from patients without CF. The 28 prospectively collected isolates were distributed amongst the following genomovars: Burkholderia cepacia genomovar I (28.6%), Burkholderia multivorans (21.4%), Burkholderia cepacia genomovar III (39.3%), Burkholderia vietnamiensis(3.6%) and Burkholderia ambifaria (7.1%). The results of this study highlight the usefulness of 16S rDNA RFLP typing for the identification of other Burkholderia spp. and non-fermenting gram-negative bacteria.

Effects of resistance exercise and creatine supplementation on myasthenia gravis: a case study

PURPOSE

The purpose of this case study was to determine the effects of 15 wk of resistance exercise and creatine (Cr) supplementation on body composition, training volume, peak strength, and complete blood chemistry in a patient with myasthenia gravis (MG).

METHODS

The patient was a 26-yr-old man who was taking prednisone and azathioprine for his condition. The patient self-administered 5 g of Cr per day in addition to resistance exercise 3 times per week. Fasting blood samples were obtained and body weight (BW) and fat free mass (FFM; via hydrostatic weighing) were measured before and after training and Cr supplementation. In addition, isokinetic (Cybex II) peak strength for leg extension (LE), leg flexion (LF), and volume load (repetition x mass lifted) for the first and last resistance training session were determined.

RESULTS

After Cr supplementation and training, the results demonstrated increases in BW (6.8%), FFM (4.3%), upper body volume load (37.0%), lower body volume load (15.0%), and peak strength for LE (37.0%) and LF (12.5%). Moreover, blood chemistry values remained within normal limits for the duration of the 15-wk study.

CONCLUSION

These data suggest that resistance exercise plus Cr supplementation may promote gains in strength and FFM in patients with MG.

Functional imaging as an aid to decision-making in metastatic paraganglioma

Malignant paraganglioma is a rare and slow growing tumour of neuroendocrine origin. At the time of diagnosis, the tumour is usually widespread, with limited therapeutic options. A variety of functional imaging studies are available for staging the disease, guiding therapy and monitoring treatment response. These include 123I-MIBG or 131I-MIBG, 111In-pentetreotide or 111In-lanreotide (somatostatin analogues), and 18F-FDG positron emission tomography. Various radionuclides, including 131I and 90Y, can be targeted to the tumour using MIBG or pentetreotide. Such targeted radionuclide therapy may provide valuable long-term palliation in such patients. We present two cases with metastatic paragangliomas who had widespread soft tissue and bone metastases. One patient was treatment naive and the second had received previous chemotherapy. The functional imaging work-up performed and the targeted radionuclide therapies considered in these patients are described. Both patients were treated with 131I-MIBG. Partial tumour response and complete symptomatic and hormonal response was achieved in one patient; in the second patient there was no change.

Long term survival of patients with advanced ovarian cancer treated with intraperitoneal radioimmunotherapy

PURPOSE: To determine the long term survival of patients with advanced ovarian cancer treated with radioimmunotherapy following cytoreductive surgery and platinum based chemotherapy. PATIENTS AND METHODS: Eligibility criteria included patients with histological evidence of ovarian cancer stages IC-IV following completion of conventional platinum containing chemotherapy. Of 52 patients entered into the study, 31 had residual disease following standard chemotherapy and 21 patients had achieved complete remission. Treatment consisted of one intraperitoneal administration of 25 mg of monoclonal antibody HMFG1 labelled with 18 mCi/m2 of 90Y. Survival was the primary end-point. RESULTS: In the group of 21 patients who had achieved complete remission following surgery, conventional chemotherapy and intraperitoneal radioimmunotherapy, the median survival has not been reached with a maximum follow-up of 12 years. Survival at greater than 10 years is 78%. CONCLUSION: This study suggests that a substantial proportion of patients who achieve complete remission with conventional therapy can achieve a long-term survival benefit when treated with intraperitoneal radioimmunotherapy using HMFG1 labelled with 90Y.

Halomethane:bisulfide/halide ion methyltransferase, an unusual corrinoid enzyme of environmental significance isolated from an aerobic methylotroph using chloromethane as the sole carbon source

A novel dehalogenating/transhalogenating enzyme, halomethane:bisulfide/halide ion methyltransferase, has been isolated from the facultatively methylotrophic bacterium strain CC495, which uses chloromethane (CH(3)Cl) as the sole carbon source. Purification of the enzyme to homogeneity was achieved in high yield by anion-exchange chromatography and gel filtration. The methyltransferase was composed of a 67-kDa protein with a corrinoid-bound cobalt atom. The purified enzyme was inactive but was activated by preincubation with 5 mM dithiothreitol and 0.5 mM CH(3)Cl; then it catalyzed methyl transfer from CH(3)Cl, CH(3)Br, or CH(3)I to the following acceptor ions (in order of decreasing efficacy): I(-), HS(-), Cl(-), Br(-), NO(2)(-), CN(-), and SCN(-). Spectral analysis indicated that cobalt in the native enzyme existed as cob(II)alamin, which upon activation was reduced to the cob(I)alamin state and then was oxidized to methyl cob(III)alamin. During catalysis, the enzyme shuttles between the methyl cob(III)alamin and cob(I)alamin states, being alternately demethylated by the acceptor ion and remethylated by halomethane. Mechanistically the methyltransferase shows features in common with cobalamin-dependent methionine synthase from Escherichia coli. However, the failure of specific inhibitors of methionine synthase such as propyl iodide, N(2)O, and Hg(2+) to affect the methyltransferase suggests significant differences. During CH(3)Cl degradation by strain CC495, the physiological acceptor ion for the enzyme is probably HS(-), a hypothesis supported by the detection in cell extracts of methanethiol oxidase and formaldehyde dehydrogenase activities which provide a metabolic route to formate. 16S rRNA sequence analysis indicated that strain CC495 clusters with Rhizobium spp. in the alpha subdivision of the Proteobacteria and is closely related to strain IMB-1, a recently isolated CH(3)Br-degrading bacterium (T. L. Connell Hancock, A. M. Costello, M. E. Lidstrom, and R. S. Oremland, Appl. Environ. Microbiol. 64:2899-2905, 1998). The presence of this methyltransferase in bacterial populations in soil and sediments, if widespread, has important environmental implications.

Rubella infection in pregnancy

It is over 50 years since a syndrome of congenital abnormalities following maternal rubella infection was first recognised. Despite the potentially devastating effects of the congenital rubella syndrome, immunisation rates are not optimal and infections in pregnancy still occur. Four cases of rubella infection occurring in pregnancy are presented. Laboratory diagnosis of primary infection and reinfection is discussed, and the need for full immunisation in childhood, and of women of child-bearing age is reiterated.

The type I and type II 11beta-hydroxysteroid dehydrogenase enzymes

Local tissue concentrations of glucocorticoids are modulated by the enzyme 11beta-hydroxysteroid dehydrogenase which interconverts cortisol and the inactive glucocorticoid cortisone in man, and corticosterone and 11-dehydrocorticosterone in rodents. The type I isoform (11beta-HSD1) is a bidirectional enzyme but acts predominantly as a oxidoreductase to form the active glucocorticoids cortisol or corticosterone, while the type II enzyme (11beta-HSD2) acts unidirectionally producing inactive 11-keto metabolites. There are no known clinical conditions associated with 11beta-HSD1 deficiency, but gene deletion experiments in the mouse indicate that this enzyme is important both for the maintenance of normal serum glucocorticoid levels, and in the activation of key hepatic gluconeogenic enzymes. Other important sites of action include omental fat, the ovary, brain and vasculature. Congenital defects in the 11beta-HSD2 enzyme have been shown to account for the syndrome of apparent mineralocorticoid excess (AME), a low renin severe form of hypertension resulting from the overstimulation of the non-selective mineralocorticoid receptor by cortisol in the distal tubule of the kidney. Inactivation of the 11beta-HSD2 gene in mice results in a phenotype with similar features to AME. In addition, these mice show high neonatal mortality associated with marked colonic distention, and remarkable hypertrophy and hyperplasia of the distal tubule epithelia. 11Beta-HSD2 also plays an important role in decreasing the exposure of the fetus to the high levels of maternal glucocorticoids. Recent work suggests a role for 11beta-HSD2 in non-mineralocorticoid target tissues where it would modulate glucocorticoid access to the glucocorticoid receptor, in invasive breast cancer and as a mechanism providing ligand for the putative 11-dehydrocorticosterone receptor. While previous homologies between members of the SCAD superfamily have been of the order of 20-30% phylogenetic analysis of a new branch of retinol dehydrogenases indicates identities of > 60% and overlapping substrate specificities. The availability of crystal structures of family members has allowed the mapping of conserved 11beta-HSD domains A-D to a cleft in the protein structure (cofactor binding domain), two parallel beta-sheets, and an alpha-helix (active site), respectively.

Altered wound arginine metabolism by corticosterone and retinoic acid

Arginine metabolism plays an important role in many aspects of inflammation and wound healing. In this study, we tested the hypothesis that steroids and vitamin A have differential effects on arginine metabolism and thereby may provide a mechanism by which steroids impair wound healing, and vitamin A improves this impairment. Rats were treated with subcutaneous corticosterone pellets 2 days prior to wounding. Intraperitoneal injections of all-trans retinoic acid in peanut oil were administered at the same time and repeated 2 and 4 days later. Polyvinyl alcohol sponges were implanted subcutaneously through a dorsal incision. On Postwounding Days 1, 5, 10, and 15, wound fluid was recovered from the sponges and assayed for nitrite/nitrate (NOx), citrulline, arginine, and ornithine concentrations as well as arginase activity. Steroid treatment decreased the metabolism of arginine to nitric oxide in the early phase of wound healing, and retinoic acid did not change this relationship. Corticosterone also decreased metabolism of arginine to ornithine in the later wound. This depression was inhibited by concomitant administration of retinoic acid. Considering the importance of nitric oxide in host defense and ornithine as a precursor for polyamine and proline synthesis, these data provide a mechanism by which vitamin A improves wound strength, but does not improve wound infection rates in steroid-treated animals.

Controversial issues in the management of pancreatic cancer: Part one. A debate held at St Mary's Hospital, London on 18 November 1993

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