Evaluation of a pharmacist-led penicillin allergy de-labelling ward round: a novel antimicrobial stewardship intervention

BACKGROUND

Antibiotic allergy labels (AALs), reported by up to 25% of hospitalized patients, are a significant barrier to appropriate prescribing and a focus of antimicrobial stewardship (AMS) programmes.

METHODS

A prospective audit of a pharmacist-led AMS penicillin allergy de-labelling ward round at Austin Health (Melbourne, Australia) was evaluated. Eligible inpatients with a documented penicillin allergy receiving an antibiotic were identified via an electronic medical report and then reviewed by a pharmacist-led AMS team. The audit outcomes evaluated were: (i) AMS post-prescription review recommendations; (ii) direct de-labelling; (iii) inpatient oral rechallenge referral; (iv) skin prick testing/intradermal testing referral; and (v) outpatient antibiotic allergy clinic assessment.

RESULTS

Across a 5 month period, 106 patients were identified from a real-time electronic prescribing antibiotic allergy report. The highest rate of penicillin allergy de-labelling was demonstrated in patients who were referred for an inpatient oral rechallenge with 95.2% (n = 21) successfully having their penicillin AAL removed. From the 22 patients with Type A reactions, 63.6% had their penicillin AAL removed. We demonstrated a significant decrease in the prescribing of restricted antibiotics (defined as third- or fourth-generation cephalosporins, fluoroquinolones, glycopeptides, carbapenems, piperacillin/tazobactam, lincosamides, linezolid or daptomycin) in patients reviewed (pre 42.5% versus post 17.9%, P = 0.0002).

CONCLUSIONS

A pharmacist-led AMS penicillin allergy de-labelling ward round reduced penicillin AALs and the prescribing of restricted antibiotics. This model could be implemented at other hospitals with existing AMS programmes.

Antimicrobial allergy 'labels' drive inappropriate antimicrobial prescribing: lessons for stewardship

BACKGROUND

The presence of antimicrobial allergy designations ('labels') often substantially reduces prescribing options for affected patients, but the frequency, accuracy and impacts of such labels are unknown.

METHODS

The National Antimicrobial Prescribing Survey (NAPS) is an annual de-identified point prevalence audit of Australian inpatient antimicrobial prescribing using standardized definitions of guideline compliance, appropriateness and indications. Data were extracted for 2 years (2013-14) and compared for patients with an antimicrobial allergy label (AAL) and with no AAL (NAAL).

RESULTS

Among 21 031 patients receiving antimicrobials (33 421 prescriptions), an AAL was recorded in 18%, with inappropriate antimicrobial use significantly higher in the AAL group versus the NAAL group (OR 1.12, 95% CI 1.05-1.22, P < 0.002). Patterns of antimicrobial use were significantly influenced by AAL, with lower β-lactam use (AAL versus NAAL; OR 0.47, 95% CI 0.43-0.50, P < 0.001) and higher quinolone (OR 2.07, 95% CI 1.83-2.34, P < 0.0001), glycopeptide (OR 1.59, 95% CI 1.38-1.83, P < 0.0001) and carbapenem (OR 1.74, 95% CI 1.43-2.13, P < 0.0001) use. In particular, among immunocompromised patients, AAL was associated with increased rates of inappropriate antimicrobial use (OR 1.68, 95% CI 1.21-2.30, P = 0.003), as well as increased use of quinolones (OR 1.88, 95% CI 1.16-3.03, P = 0.02) and glycopeptides (OR 1.82, 95% CI 1.17-2.84, P = 0.01).

CONCLUSIONS

AALs are common and appear to be associated with higher rates of inappropriate prescribing and increased use of broad-spectrum antimicrobials. Improved accuracy in defining AALs is likely to be important for effective antimicrobial stewardship (AMS), with efforts to 'de-label' inappropriate AAL patients a worthwhile feature of future AMS initiatives.

Acute Flaccid Paralysis: The New, The Old, and The Preventable

Acute flaccid paralysis (AFP) has a changing epidemiology with ongoing polio outbreaks and emerging causes such as nonpolio enteroviruses and West Nile virus (WNV). We report a case of AFP from the Horn of Africa that was initially classified as probable polio but subsequently found to be due to WNV.

Is fosfomycin a potential treatment alternative for multidrug-resistant gram-negative prostatitis?

BACKGROUND

Multidrug-resistant gram-negative bacterial (MDR-GNB) infections of the prostate are an increasing problem worldwide, particularly complicating transrectal ultrasound (TRUS)-guided prostate biopsy. Fluoroquinolone-based regimens, once the mainstay of many protocols, are increasingly ineffective. Fosfomycin has reasonable in vitro and urinary activity (minimum inhibitory concentration breakpoint ≤64 µg/mL) against MDR-GNB, but its prostatic penetration has been uncertain, so it has not been widely recommended for the prophylaxis or treatment of MDR-GNB prostatitis.

METHODS

In a prospective study of healthy men undergoing a transurethral resection of the prostate for benign prostatic hyperplasia, we assessed serum, urine, and prostatic tissue (transition zone [TZ] and peripheral zone [PZ]) fosfomycin concentrations using liquid chromatography-tandem mass spectrometry, following a single 3-g oral fosfomycin dose within 17 hours of surgery.

RESULTS

Among the 26 participants, mean plasma and urinary fosfomycin levels were 11.4 ± 7.6 µg/mL and 571 ± 418 µg/mL, 565 ± 149 minutes and 581 ± 150 minutes postdose, respectively. Mean overall prostate fosfomycin levels were 6.5 ± 4.9 µg/g (range, 0.7-22.1 µg/g), with therapeutic concentrations detectable up to 17 hours following the dose. The mean prostate to plasma ratio was 0.67 ± 0.57. Mean concentrations within the TZ vs PZ prostate regions varied significantly (TZ, 8.3 ± 6.6 vs PZ, 4.4 ± 4.1 µg/g; P = .001). Only 1 patient had a mean prostatic fosfomycin concentration of <1 µg/g, whereas the majority (70%) had concentrations ≥4 µg/g.

CONCLUSIONS

Fosfomycin appears to achieve reasonable intraprostatic concentrations in uninflamed prostate following a single 3-g oral dose, such that it may be a potential option for prophylaxis pre-TRUS prostate biopsy and possibly for the treatment of MDR-GNB prostatitis. Formal clinical studies are now required.

Enterococcal bacteraemia: factors influencing mortality, length of stay and costs of hospitalization

Enterococci are a major cause of nosocomial bacteraemia. The impacts of vanB vancomycin resistance and antibiotic therapy on outcomes in enterococcal bacteraemia are unclear. Factors that affect length of stay (LOS) and costs of managing patients with enterococcal bacteraemia are also unknown. This study aimed to identify factors associated with mortality, LOS and hospitalization costs in patients with enterococcal bacteraemia and the impact of vancomycin resistance and antibiotic therapy on these outcomes. Data from 116 patients with vancomycin-resistant Enterococci (VRE), matched 1:1 with patients with vancomycin-susceptible Enterococcus (VSE), from two Australian hospitals were reviewed for clinical and economic outcomes. Univariable and multivariable logistic and quantile regression analyses identified factors associated with mortality, LOS and costs. Intensive care unit admission (OR, 8.57; 95% CI, 3.99-18.38), a higher burden of co-morbidities (OR, 4.55; 95% CI, 1.83-11.33) and longer time to appropriate antibiotics (OR, 1.02; 95% CI, 1.01-1.03) were significantly associated with mortality in enterococcal bacteraemia. VanB vancomycin resistance increased LOS (4.89 days; 95% CI, 0.56-11.52) and hospitalization costs (AU$ 28 872; 95% CI, 734-70 667), after adjustment for confounders. Notably, linezolid definitive therapy was associated with lower mortality (OR, 0.13; 95% CI, 0.03-0.58) in vanB VRE bacteraemia patients. In patients with VSE bacteraemia, time to appropriate antibiotics independently influenced mortality, LOS and hospitalization costs, and underlying co-morbidities were associated with mortality. The study findings highlight the importance of preventing VRE bacteraemia and the significance of time to appropriate antibiotics in the management of enterococcal bacteraemia.

Significant reduction in vancomycin-resistant enterococcus colonization and bacteraemia after introduction of a bleach-based cleaning-disinfection programme

BACKGROUND

Vancomycin-resistant enterococcus (VRE) colonization and infection have increased at our hospital, despite adherence to standard VRE control guidelines.

AIM

We implemented a multi-modal, hospital-wide improvement programme including a bleach-based cleaning-disinfection programme ('Bleach-Clean'). VRE colonization, infection and environmental contamination were compared pre and post implementation.

METHODS

The programme included a new product (sodium hypochlorite 1000 ppm + detergent), standardized cleaning-disinfection practices, employment of cleaning supervisors, and modified protocols to rely on alcohol-based hand hygiene and sleeveless aprons instead of long-sleeved gowns and gloves. VRE was isolated using chromogenic agar and/or routine laboratory methods. Outcomes were assessed during the 6 months pre and 12 months post implementation, including proportions (per 100 patients screened) of VRE colonization in high-risk wards (HRWs: intensive care, liver transplant, renal, haematology/oncology); proportions of environmental contamination; and episodes of VRE bacteraemia throughout the entire hospital.

FINDINGS

Significant reductions in newly recognized VRE colonizations (208/1948 patients screened vs 324/4035, a 24.8% reduction, P = 0.001) and environmental contamination (66.4% reduction, P = 0.012) were observed, but the proportion of patients colonized on admission was stable. The total burden of inpatients with VRE in the HRWs also declined (median percentage of colonized inpatients per week, 19.4% vs 17.3%, P = 0.016). Hospital-wide VRE bacteraemia declined from 14/2935 patients investigated to 5/6194 (83.1% reduction; P < 0.001), but there was no change in vancomycin-susceptible enterococcal bacteraemia (P = 0.54).

CONCLUSION

The Bleach-Clean programme was associated with marked reductions in new VRE colonizations in high-risk patients, and VRE bacteraemia across the entire hospital. These findings have important implications for VRE control in endemic healthcare settings.

Doxycycline vs. macrolides in combination therapy for treatment of community-acquired pneumonia

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

Association between severe pandemic 2009 influenza A (H1N1) virus infection and immunoglobulin G(2) subclass deficiency

BACKGROUND

. Severe pandemic 2009 influenza A virus (H1N1) infection is associated with risk factors that include pregnancy, obesity, and immunosuppression. After identification of immunoglobulin G(2) (IgG(2)) deficiency in 1 severe case, we assessed IgG subclass levels in a cohort of patients with H1N1 infection.

METHODS

Patient features, including levels of serum IgG and IgG subclasses, were assessed in patients with acute severe H1N1 infection (defined as infection requiring respiratory support in an intensive care unit), patients with moderate H1N1 infection (defined as inpatients not hospitalized in an intensive care unit), and a random sample of healthy pregnant women.

RESULTS

Among the 39 patients with H1N1 infection (19 with severe infection, 7 of whom were pregnant; 20 with moderate infection, 2 of whom were pregnant), hypoabuminemia (P < .001), anemia (P < .001), and low levels of total IgG (P= .01), IgG(1) (P= .022), and IgG(2) (15 of 19 vs 5 of 20; P= .001; mean value +/- standard deviation [SD], 1.8 +/- 1.7 g/L vs 3.4 +/- 1.4 g/L; P= .003) were all statistically significantly associated with severe H1N1 infection, but only hypoalbuminemia (P= .02) and low mean IgG(2) levels (P= .043) remained significant after multivariate analysis. Follow-up of 15 (79%) surviving IgG(2)-deficient patients at a mean (+/- SD) of 90 +/- 23 days (R, 38-126) after the initial acute specimen was obtained found that hypoalbuminemia had resolved in most cases, but 11 (73%) of 15 patients remained IgG(2) deficient. Among 17 healthy pregnant control subjects, mildly low IgG(1) and/or IgG(2) levels were noted in 10, but pregnant patients with H1N1 infection had significantly lower levels of IgG(2) (P= .001).

CONCLUSIONS

Severe H1N1 infection is associated with IgG(2) deficiency, which appears to persist in a majority of patients. Pregnancy-related reductions in IgG(2) level may explain the increased severity of H1N1 infection in some but not all pregnant patients. The role of IgG(2) deficiency in the pathogenesis of H1N1 infection requires further investigation, because it may have therapeutic implications.

A quantitative assessment of the efficacy of surgical and N95 masks to filter influenza virus in patients with acute influenza infection

We assessed the in vivo efficacy of surgical and N95 (respirator) masks to filter reverse transcription-polymerase chain reaction (RT-PCR)-detectable virus when worn correctly by patients with laboratory-confirmed acute influenza. Of 26 patients with a clinical diagnosis of influenza, 19 had the diagnosis confirmed by RT-PCR, and 9 went on to complete the study. Surgical and N95 masks were equally effective in preventing the spread of PCR-detectable influenza.

Clostridium lavalense sp. nov., a glycopeptide-resistant species isolated from human faeces

Two vancomycin-resistant, strictly anaerobic, Gram-positive, rod-shaped, spore-forming organisms (strains CCRI-9842(T) and CCRI-9929) isolated from human faecal specimens in Québec, Canada, and Australia were characterized using phenotypic, biochemical and molecular taxonomic methods. Pairwise analysis of the 16S rRNA gene sequences showed that both strains were closely related to each other genetically (displaying 99.2 % sequence similarity) and represented a previously unknown subline within the Clostridium coccoides rRNA group of organisms (rRNA cluster XIVa of the genus Clostridium). Strains CCRI-9842(T) and CCRI-9929 used carbohydrates as fermentable substrates, producing acetic acid as the major product of glucose metabolism. The novel strains were most closely related to Clostridium asparagiforme, Clostridium bolteae and Clostridium clostridioforme, but morphological, biochemical and phylogenetic studies demonstrated that they represent a previously unidentified species of the genus Clostridium. This was confirmed by the unique cellular fatty acid composition of strains CCRI-9842(T) and CCRI-9929. Therefore, on the basis of data from the polyphasic taxonomic analysis, it is proposed that strains CCRI-9842(T) and CCRI-9929 represent a novel species of the genus Clostridium, for which the name Clostridium lavalense sp. nov. is proposed. The type strain is CCRI-9842(T) (=CCUG 54291(T)=JCM 14986(T)=NML 03-A-015(T)).

The etiology of community-acquired pneumonia in Australia: why penicillin plus doxycycline or a macrolide is the most appropriate therapy

BACKGROUND

Available data on the etiology of community-acquired pneumonia (CAP) in Australia are very limited. Local treatment guidelines promote the use of combination therapy with agents such as penicillin or amoxycillin combined with either doxycycline or a macrolide.

METHODS

The Australian CAP Study (ACAPS) was a prospective, multicenter study of 885 episodes of CAP in which all patients underwent detailed assessment for bacterial and viral pathogens (cultures, urinary antigen testing, serological methods, and polymerase chain reaction). Antibiotic agents and relevant clinical outcomes were recorded.

RESULTS

The etiology was identified in 404 (45.6%) of 885 episodes, with the most frequent causes being Streptococcus pneumoniae (14%), Mycoplasma pneumoniae (9%), and respiratory viruses (15%; influenza, picornavirus, respiratory syncytial virus, parainfluenza virus, and adenovirus). Antibiotic-resistant pathogens were rare: only 5.4% of patients had an infection for which therapy with penicillin plus doxycycline would potentially fail. Concordance with local antibiotic recommendations was high (82.4%), with the most commonly prescribed regimens being a penicillin plus either doxycycline or a macrolide (55.8%) or ceftriaxone plus either doxycycline or a macrolide (36.8%). The 30-day mortality rate was 5.6% (50 of 885 episodes), and mechanical ventilation or vasopressor support were required in 94 episodes (10.6%). Outcomes were not compromised by receipt of narrower-spectrum beta-lactams, and they did not differ on the basis of whether a pathogen was identified.

CONCLUSIONS

The vast majority of patients with CAP can be treated successfully with narrow-spectrum beta-lactam treatment, such as penicillin combined with doxycycline or a macrolide. Greater use of such therapy could potentially reduce the emergence of antibiotic resistance among common bacterial pathogens.

Can alcohol-based hand-rub solutions cause you to lose your driver's license? Comparative cutaneous absorption of various alcohols

We assessed cutaneous ethanol (ETOH) and isopropanol (ISOP) absorption after intensive (30 times per h) use of alcohol-based hand-rub solutions by healthcare workers (HCWs). ETOH was detectable in the breath of 6/20 HCWs (0.001 to 0.0025%) at 1 to 2 min postexposure and in the serum of 2/20 HCWs at 5 to 7 min postexposure. Serum ISOP levels were unrecordable at all time points.

Low rates of cutaneous adverse reactions to alcohol-based hand hygiene solution during prolonged use in a large teaching hospital

We assessed cutaneous adverse reactions (CARs) to alcohol-based hand rub (ABHR) after the introduction of a hand hygiene culture change program at our institution. CARs were infrequent among exposed health care workers (HCWs) (13/2,750; 0.47%; 1 CAR per 72 years of HCW exposure) and were not influenced by the duration or intensity of ABHR use but were associated with the presence of irritant contact dermatitis.

Molecular characterization of vanB elements in naturally occurring gut anaerobes

Previously, we reported the isolation of 10 vancomycin-resistant gram-positive anaerobic bacilli carrying the vanB ligase gene from nine hemodialysis patients (S. A. Ballard et al., Antimicrob. Agents Chemother. 49:77-81, 2005; T. P. Stinear et al., Lancet 357:855-856, 2001). In the present study, the molecular and evolutionary relationship of the vanB resistance element within these 10 anaerobes and two vancomycin-resistant Enterococcus faecium strains were examined. PCR analysis and nucleotide sequencing demonstrated that all 12 isolates carried the vanB operon associated with an element identical to Tn1549 and Tn5382 of Enterococcus. Restriction fragment length polymorphism analysis of the vanB operon in these isolates revealed two distinct patterns, and sequencing showed that minor base differences existed. PCR amplification of the joint region of a circular intermediate was demonstrated in nine of these organisms, a finding indicative of an ability to excise and circularize, an intermediate step in transposition and conjugative transfer. Southern hybridization with a vanB-vanX(B) probe suggests that there is one insert of the transposon in all isolates. Sequence analysis of the integration site revealed distinct sequences: the Tn1549/5382 element within E. faecium was inserted within the host chromosome, whereas nucleotide sequences surrounding the Tn1549/5382 element in the 10 anaerobes showed no significant homology to sequences in the GenBank database. We demonstrate considerable similarity between the Tn1549/5382 element identified in 10 anaerobe isolates with that found in enterococci. The homology and potential to transpose suggest a recent horizontal transfer event may have occurred. However, the original direction of transposition and the mechanism involved remains unknown.

Low-level vancomycin resistance in Staphylococcus aureus--an Australian perspective

Low-level vancomycin resistance in Staphylococcus aureus has emerged as a clinical problem over the past 8 years. The clinical relevance of this resistance has been questioned, and laboratory detection remains difficult and time consuming. There is, however, increasing evidence linking low-level vancomycin resistance with glycopeptide treatment failure in serious Staphylococcus aureus infections. Diagnostic laboratories and clinicians need to be aware of this resistance phenotype, to have procedures in place to detect the resistance, and to have strategies for managing patients with infections caused by resistant strains.

Comparison of three PCR primer sets for identification of vanB gene carriage in feces and correlation with carriage of vancomycin-resistant enterococci: interference by vanB-containing anaerobic bacilli

We assessed the sensitivities and specificities of three previously described PCR primers on enrichment broth cultures of feces for the accurate detection of fecal carriage of vancomycin-resistant enterococci (VRE). In addition, we investigated specimens that were vanB PCR positive but VRE culture negative for the presence of other vanB-containing pathogens. Feces from 59 patients (12 patients carrying vanB Enterococcus faecium strains and 47 patients negative for VRE carriage) were cultured for 36 h in aerobic brain heart infusion (BHI) broth, anaerobic BHI (AnO(2)BHI) broth, or aerobic Enterococcosel (EC) broth. DNA was extracted from the cultures and tested for the presence of vanB by using the PCR primers of Dutka-Malen et al. (S. Dutka-Malen, S. Evers, and P. Courvalin, J. Clin. Microbiol. 33:24-27, 1995), Bell et al. (J. M. Bell, J. C. Paton, and J. Turnidge, J. Clin. Microbiol. 36:2187-2190, 1998), and Stinear et al. (T. P. Stinear, D. C. Olden, P. D. R. Johnson, J. K. Davies, and M. L. Grayson, Lancet 357:855-856, 2001). The sensitivity (specificity) of PCR compared with the results of culture on BHI, AnO(2)BHI, and EC broths were 67% (96%), 50% (94%), and 17% (100%), respectively, with the primers of Dutka-Malen et al.; 92% (60%), 92% (45%), and 92% (83%), respectively, with the primers of Bell et al.; and 92% (49%), 92% (43%), and 100% (51%) respectively, with the primers of Stinear et al. The primers of both Bell et al. and Stinear et al. were significantly more sensitive than those of Dutka-Malen et al. in EC broth (P = 0.001 and P < 0.001, respectively). The poor specificities for all primer pairs were due in part to the isolation and identification of six anaerobic gram-positive bacilli, Clostridium hathewayi (n = 3), a Clostridium innocuum-like organism (n = 1), Clostridium bolteae (n = 1), and Ruminococcus lactaris-like (n = 1), from five fecal specimens that were vanB positive but VRE culture negative. All six organisms were demonstrated to contain a vanB gene identical to that of VRE. VanB-containing bowel anaerobes may result in false-positive interpretation of PCR-positive fecal enrichment cultures as VRE, regardless of the primers and protocols used.

Treatment failure due to methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin

We report the first instance in Australia of treatment failure due to a strain of methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin--heteroresistant vancomycin-intermediate S. aureus (hVISA). The infection occurred in a 41-year-old man with multiple risk factors. No transmission of the organism to other patients or the environment was detected. This case may herald the beginning of a new phase of staphylococcal resistance in Australia.

The prevalence of fecal colonization with VRE among residents of long-term-care facilities in Melbourne, Australia

A point-prevalence survey performed among residents of eight nursing homes in Melbourne, Australia, found a rate of fecal VRE colonization of 3.1% (9/292; 95% confidence interval, 1.1-5.1), all vanB Enterococcusfaecium. This is a higher rate than in the general community (3.1% vs 0.2%). Many residents (16%) had been inpatients in acute-care hospitals in the previous 3 months.

Assessing the risk of tuberculosis infection among healthcare workers: the Melbourne Mantoux Study. Melbourne Mantoux Study Group

OBJECTIVE

To determine the potential prevalence of nosocomial infection with Mycobacterium tuberculosis among hospital employees in teaching hospitals in Melbourne.

DESIGN

Cross-sectional survey of positive tuberculin skin test (Mantoux) responses among employees in 14 public hospitals in Melbourne, January 1996 to April 1999.

PARTICIPANTS

All consenting employees in participating hospitals (4,070 healthcare and 4,298 non-healthcare workers; participation rates, 13%-66%).

OUTCOME MEASURES

Prevalence of positive responses to tuberculin skin tests among healthcare and non-healthcare workers and association with employee and hospital characteristics.

RESULTS

Healthcare workers were significantly more likely to have a positive tuberculin response than non-healthcare workers (19.3% versus 13.7%; odds ratio, 1.5; 95% CI, 1.3-1.7; P<0.001). Multivariable analysis revealed that age, country of birth (high versus low tuberculosis [TB] prevalence), history of BCG (bacille Calmette-Guérin) vaccination, years since last BCG, occupation (healthcare versus non-healthcare worker) and years of hospital employment were all significantly associated with a positive response. Rates of positive responses among employees varied greatly between hospitals (6%-35%). These differences were not explained by employee characteristics, hospital TB patient load (number of admissions or bed-days) or percentage of hospital patients from countries with high TB prevalence. The hospital with the highest rate of positive responses was notable for its lack of negative-pressure isolation rooms for TB patients.

CONCLUSIONS

Positive tuberculin responses are relatively common among hospital employees in Melbourne, with rates varying between hospitals and being higher among healthcare than non-healthcare workers. Employee characteristics, such as age, country of birth and past BCG status, explain little of this variation. More emphasis on TB infection control measures and regular staff screening may be needed.

Enterococcal vanB resistance locus in anaerobic bacteria in human faeces

While developing a rapid method to detect carriers of vancomycin-resistant enterococci (VRE), we found the vanB gene by PCR in 13 of 50 human faecal specimens that did not contain culturable VRE. Passaging under antibiotic selection allowed us to isolate two species of anaerobic bacteria that were vanB PCR positive, vancomycin resistant, and teicoplanin sensitive. Sequence analysis of the 16S rRNA genes showed that one isolate resembled Eggerthella lenta (98% identity), and the other Clostridium innocuum (92% identity). Southern hybridisation and nucleotide sequencing showed a vanB locus homologous to that in VRE. We propose that vanB resistance in enterococci might arise from gene transfer in the human bowel.

A paired comparison of tuberculin skin test results in health care workers using 5 TU and 10 TU tuberculin

BACKGROUND

Historically, 10 TU has been employed in Australia and the United Kingdom to perform the tuberculin skin test (TST). However, this makes it difficult to compare the rates of TST positivity with other countries such as the USA who use 5 TU. To assess the impact of the dose of tuberculin on the TST a comparison was made of TST responses in health care workers given a TST with both 5 and 10 TU.

METHODS

Two TSTs were performed simultaneously in each health care worker using 5 and 10 TU. Each dose was randomly assigned in a blinded manner to the right or left forearm and read at 48-72 hours by a single nurse who was blinded to the assignment of the 5 and 10 TU doses.

RESULTS

A total of 128 health care workers were enrolled, 119 (93%) of whom had a past history of BCG vaccination. The overall mean difference in paired reaction sizes for the two doses was 1.5 mm with 95% limits of agreement of -3.6 to 6.5 mm.

CONCLUSION

A slightly larger TST reading was seen with 10 TU than with 5 TU. The mean difference of 1.5 mm between the two doses should be considered when comparing rates of TST positivity between countries who use different doses of tuberculin to perform the tuberculin skin test.

Effect of anti-tuberculosis treatment on the tuberculin interferon-gamma response in tuberculin skin test (TST) positive health care workers and patients with tuberculosis

SETTING

Public hospital, Victoria, Australia.

OBJECTIVE

To evaluate the effect of multidrug treatment and isoniazid (INH) chemoprophylaxis on the tuberculin interferon-y assay (QIFN) in 19 patients with culture-confirmed Mycobacterium tuberculosis and 119 health care workers (HCWs) with tuberculin skin tests (TST) > or =15 mm.

DESIGN

Patients with M. tuberculosis were treated with standard medication and tested with QIFN at diagnosis and at regular intervals over a 12-month period. All HCWs, 59 (50%) of whom were prescribed INH chemoprophylaxis, were tested with QIFN at baseline, 2, 4, 6 and 12 months.

RESULTS

QIFN results in patients with tuberculosis were consistent and reproducible. At the initial time point QIFN assays were positive for M. tuberculosis in 67%, and once positive, the QIFN assay remained so over the 12-month period. In the HCWS, initial QIFN assays were positive in 73 (61%). During the 12-month study, 91 HCWs had a QIFN assay on at least two occasions. The overall reproducibility between tests was fair (kappa statistic = 0.45), and was little affected by administration of INH.

CONCLUSION

These data suggest that although the QIFN assay is generally positive in patients with proven tuberculosis, it does not provide clinically useful information during the first 12 months of treatment with multidrug chemotherapy or INH chemoprophylaxis.

A comparison of two dosing regimens of zidovudine in Thai adults with early symptomatic HIV infection. Conducting clinical HIV trials in South-East Asia

AIM

To compare the clinical and immunological efficacy, and tolerance of two dosage regimens of zidovudine (ZDV) in an adult Thai population with early symptomatic human immunodeficiency virus (HIV) disease and to identify important clinical issues associated with conducting HIV trials in South-East Asia.

METHODS

HIV-infected Thai adults, with early symptomatic HIV disease and CD4 lymphocyte counts less than 400/mm3, who were managed in the infectious diseases clinics at two university teaching hospitals in Bangkok, Thailand, were enrolled in a randomised, open-label, dose-regimen comparison trial of ZDV. Two oral ZDV dosing regimens: regimen A, 100 mg tid+200 mg nocte (ZDV-A) vs regimen B, 250 mg bid (ZDV-B) were compared. The main outcome measures were: 1. Clinical efficacy: rate of progression to acquired immunodeficiency syndrome (AIDS) or death. 2. Immunologic efficacy: changes in CD4 lymphocyte numbers compared to baseline; rate of decline of CD4 lymphocyte numbers to less than 100/mm3. 3. Toxicity, as defined by clinical symptomatology and laboratory parameters.

RESULTS

Two hundred and four patients were enrolled (103 ZDV-A; 101 ZDV-B) of whom 195 were followed beyond baseline. Patients were typical of those encountered with HIV in Thailand: mean age 33 years; 89% male; 88% heterosexual HIV acquisition; mean baseline CD4 lymphocyte count 241/mm3. Follow-up while on therapy was comparable for the two groups (mean+/-SD): 533+/-236 days (ZDV-A) vs 592+/-210 days (ZDV-B). One hundred and eleven patients (57%; 51 ZDV-A; 60 ZDV-B) were treated for at least 22 months (669+/-30 days). Clinical and immunological outcomes for ZDV-A and ZDV-B, including rate of progression to AIDS or death, development of non-AIDS-defining opportunistic infections, mean changes in CD4 lymphocyte numbers/mm3, difference in area under the CD4:time distribution curve and difference in the rate of decline of CD4 lymphocyte numbers to less than 100/mm3, were not significantly different. The presence of oral hairy leukoplakia or unintentional weight loss of 10-20% at enrollment were significantly associated with the later development of AIDS (p=0.03 and 0.04, respectively). ZDV-associated toxicity was similar for both regimens. Maintaining protocol adherence and appropriate clinical follow-up emerged as important practical issues.

CONCLUSION

In Thai adults, ZDV 100 mg tid+200 mg nocte and ZDV 250 mg bid have similar clinical and immunological efficacy. Rates of ZDV toxicity are comparable to those reported in non-Asian populations. Despite limitations in medical care access and maintaining long-term follow-up, successful trials of antiretroviral agents are feasible in South-East Asia and multi-drug treatment trials should be pursued in appropriate institutions.

Fecal colonization with vancomycin-resistant enterococci in Australia

To assess the rate of fecal vancomycin-resistant enterococci (VRE) colon ization in Austalia, we examined specimens from 1,085 healthy volunteers. VRE was cultured from 2(0.2%) of 1,085 specimens; both were vanB Enter ococcus faecium, identical by pulsed-field gel electrophoresis, but with a pattern rare in Melbourne hospitals.

Tuberculin-purified protein derivative-, MPT-64-, and ESAT-6-stimulated gamma interferon responses in medical students before and after Mycobacterium bovis BCG vaccination and in patients with tuberculosis

QuantiFERON-TB (QIFN) (CSL Limited) is a whole-blood assay for the recognition of infection with Mycobacterium tuberculosis. QIFN measures gamma interferon (IFN-gamma) production when purified protein derivatives (PPDs) of mycobacteria are incubated with venous blood samples. The specificity of QIFN in medical students before and after BCG immunization was assessed, and sensitivity in patients with tuberculosis was assessed. Antigens were PPD derived from M. tuberculosis and two M. tuberculosis-specific proteins, ESAT-6 and MPT-64. Of 60 medical students, all of whom had 0-mm tuberculin skin tests (TSTs) at study entry, 58 (97%) were initially classified as negative for M. tuberculosis infection by PPD QIFN. Five months after BCG immunization, 7 of 54 students (13%) had a TST result of >/=10 mm and 11 of 54 students (20%) tested positive by PPD QIFN. ESAT-6- and MPT-64-stimulated IFN-gamma responses in the medical students were negative prior to and after BCG immunization. For patients with active tuberculosis, 12 of 19 (63%) were positive by PPD QIFN, 11 of 19 (58%) were positive by ESAT-6 QIFN, and 0 of 12 were positive by MPT-64 QIFN. In conclusion, PPD QIFN was negative in 97% of a low-risk population who had not received BCG and who had negative TSTs. The specificities of both the TST and PPD QIFN were reduced following BCG immunization. PPD QIFN and ESAT-6 QIFN were of similar and moderate sensitivity in patients with active tuberculosis, but ESAT-6 QIFN is likely to be more specific because it is not influenced by past BCG exposure.

Outcome of a screening program for vancomycin-resistant enterococci in a hospital in Victoria

OBJECTIVE

To screen for faecal colonisation with vancomycin-resistant enterococci (VRE) among potentially at-risk patients.

DESIGN

Infection control screening program.

SETTING

Monash Medical Centre (a tertiary care hospital), Melbourne, Victoria, in the seven months from June 1997.

PATIENTS

Patients in the Renal, Oncology and Intensive Care (ICU) Units.

MAIN OUTCOME MEASURES

Presence of VRE in a rectal swab or faecal specimen taken at admission and at regular intervals during inpatient stay; presence of vancomycin-resistance genes (vanA, vanB and vanC) assessed by polymerase chain reaction (PCR); genetic clonality of isolates assessed by pulsed-field gel electrophoresis (PFGE).

RESULTS

574 patients (356 renal, 134 ICU and 84 oncology) were screened; 12 were colonised with VRE--nine renal inpatients, two having peritoneal dialysis or incentre haemodialysis, and one ICU patient. Nine isolates were Enterococcus faecalis (seven positive for vanB and two negative for all three resistance genes) and three were Enterococcus faecium (all positive for vanB). Eight were high-level gentamicin resistant. PFGE suggested genetic clonality between the index isolate and five other isolates from renal patients. No specific clinical practice was associated with VRE colonisation. Attempts to clear rectal carriage with oral ampicillin/amoxycillin or bacitracin were of limited success. Although antibiotic prescribing in the Renal Unit was generally consistent with defined protocols, use of vancomycin and third-generation cephalosporins has been further restricted.

CONCLUSIONS

Renal inpatients in our institution appear most at risk of VRE colonisation (4.6% overall) and therefore of VRE infection. Routine screening, especially of potentially high-risk patients, should be considered in major Australian hospitals.

Diarrheal disease in patients infected with human immunodeficiency virus in Bangkok, Thailand

Diarrheal disease and its associated morbidities occur frequently in patients infected with human immunodeficiency virus (HIV) and may be associated with a decreased quality of life. We studied the spectrum of symptoms, measures of nutritional status, and the enteric pathogens associated with diarrheal disease in a group of 24 patients infected with HIV in Bangkok, Thailand compared with a group of 19 patients infected with HIV without diarrhea cared for at the same clinic. Patients with diarrhea appeared to have more advanced disease by CD4 cell counts and complained more frequently of symptoms such as anorexia, gas, and bloating than patients without diarrhea. Patients with diarrhea had a tendency toward a lower nutritional status, as measured by body mass index and mid arm circumference. Stool culture and examination revealed that enteric pathogens including Salmonella species and Cryptosporidium parvum sporidia were recovered at equal frequencies in patients with and without diarrhea (27% of the patients with diarrhea and 25% of the patients without diarrhea). Microsporidia was identified in one patient with diarrhea. It was not possible to identify a pathogen in 73% of the patients with diarrhea and 75% of the patients without diarrhea, suggesting that additional agents or factors may be responsible for the diarrheal symptoms in the patients with diarrhea. More extensive studies to identify potentially treatable pathogens in HIV-infected patients with diarrhea in Thailand are warranted and further attempts to better define the syndrome of pathogen-negative diarrheal disease in patients infected with HIV might result in the development of more targeted interventions in these patients.

Isoniazid toxicity in health care workers

The toxicity of isoniazid chemoprophylaxis was assessed in 83 health care workers (HCWs) receiving a 6-month course, in whom clinical toxicity and liver function were monitored. Thirty-four HCWs (41%) developed an adverse event; in 26 (76%), toxicity was sufficiently severe to require cessation of treatment. Of the total, liver function test abnormalities (serum alanine transaminase levels more than two times normal) were evident in 14 subjects, with 8 requiring cessation of therapy. Other symptoms reported included malaise, nausea with associated anorexia, arthralgia, and rash. Mean time to development of symptoms was 3 weeks (range, 0.5-6 weeks), with the mean age of those with toxicity not differing significantly from those without (38 vs. 39 years). The high rate of toxicity seen in this study is sufficiently notable that we advocate the use of monthly liver function testing and frequent review in those receiving isoniazid prophylactic therapy.

The clinical efficacy of continuous-infusion flucloxacillin in serious staphylococcal sepsis

Since the efficacy of beta-lactams against pathogens such as methicillin-susceptible Staphylococcus aureus (MSSA) is related to the time for which serum drug concentrations exceed the MIC for the pathogen, administration of anti-staphylococcal beta-lactams by continuous infusion may provide a more suitable means of drug delivery than intermittent dosing. To assess the clinical efficacy of continuous-infusion therapy, we reviewed the outcomes for 20 consecutive patients with proven serious MSSA sepsis (three with endocarditis, ten osteomyelitis, one endocarditis plus osteomyelitis and six deep abscess) treated with continuous-infusion flucloxacillin (8-12 g/day). Patients initially receiving routine intermittent-dose flucloxacillin therapy were changed to continuous-infusion flucloxacillin (mean duration 29 days; range 4-60 days) for completion of their treatment course. In the majority of cases this was given at home. Serum flucloxacillin concentrations during continuous-infusion flucloxacillin 12 g/day were 11.5->40 mg/L (ten patients) and those during continuous-infusion flucloxacillin 8 g/day were 8->40 mg/L (five patients), these concentrations being well above the expected MIC of flucloxacillin for MSSA. Continuous-infusion flucloxacillin was well tolerated by most patients, and 14/17 patients (82%) who completed their course of continuous-infusion flucloxacillin were judged clinically and microbiologically cured at long-term follow-up (mean 67 weeks; range 4-152 weeks). These preliminary data suggest that, following initial intermittent-dose flucloxacillin therapy, continuous-infusion flucloxacillin is an effective treatment option for serious MSSA sepsis, and forms a feasible and possibly preferable alternative to glycopeptides when considering home-based parenteral therapy for these infections. Further studies are needed to identify whether continuous-infusion flucloxacillin can entirely replace intermittent-dose therapy for such infections.