Sickness presenteeism associated with influenza-like illness in veterinarians working in New South Wales: Results of a state-wide survey

BACKGROUND

Sickness presenteeism in the veterinary profession potentially jeopardises the wellbeing of veterinary team members and endangers quality of patient care. In veterinary team members with influenza-like illness (ILI), sickness presenteeism poses a risk to the health and wellbeing of colleagues and clients, particularly in the context of the COVID-19 pandemic. This study aimed to evaluate factors associated with sickness presenteeism in NSW registered veterinarians suffering from ILI, both before and since the beginning of the COVID-19 pandemic.

METHODS

Veterinarians registered in NSW were invited to complete an anonymous online mixed-methods survey between 31 March 2021 and 31 June 2021, regarding sickness presenteeism and absenteeism associated with ILI. The questionnaire was distributed through online and print newsletters of the Australian Veterinary Association NSW Branch and the NSW Veterinary Practitioners Board.

RESULTS

From a total of 122 participants, 81 veterinarians (66.4%) reported that they would attend work despite displaying symptoms of ILI. Most veterinarians would stay at home with a fever alone (n = 108, 88.5%), however, many would still attend work with a sore throat (n = 121, 99.2%) or a dry cough (n = 91, 74.6%). Sickness presenteeism was significantly associated with lack of staff to cover workers. Although sickness presenteeism remained common, participants reported that they were less likely to attend work with symptoms of ILI since the beginning of the COVID-19 pandemic.

DISCUSSION

The data are discussed in relation to sickness presenteeism in healthcare workers. These findings underscore an urgent need for relief staff to decrease sickness presenteeism.

Evaluation of the Haemophilus influenzae EUCAST and CLSI disc diffusion methods to recognize aminopenicillin and amoxicillin/clavulanate resistance

OBJECTIVES

Implementation of EUCAST susceptibility testing in an Australian hospital laboratory demonstrated higher rates of aminopenicillin and amoxicillin/clavulanate resistance in Haemophilus influenzae than previously recognized. This study aimed to better define the variability in the detection of β-lactam resistance based on EUCAST and CLSI disc diffusion (DD) methodology, by comparison with the recommended reference method, broth microdilution (BMD), and by concordance with genomic analysis.

METHODS

A total of 100 random H. influenzae isolates were assessed for ampicillin and amoxicillin/clavulanate susceptibility by EUCAST and CLSI DD and BMD. WGS was used to analyse the ftsI gene of a subset of isolates with β-lactam resistance, other than that due to isolated β-lactamase production.

RESULTS

Of the 100 isolates, 32 were categorized as either β-lactamase negative, ampicillin resistant (BLNAR) (n = 18) or β-lactamase positive, amoxicillin/clavulanate resistant (BLPACR) (n = 14) by EUCAST DD. All 18 EUCAST BLNAR isolates were genotypically confirmed by WGS. Five of 18 BLNAR isolates were concordant by CLSI DD, 12 by EUCAST BMD and 4 by CLSI BMD. Nine of 14 EUCAST BLPACR isolates were confirmed by WGS; the remaining 5 were 1 mm below the EUCAST DD breakpoint. Only one isolate was detected as BLPACR by CLSI DD. Group III mutations associated with high-level ampicillin resistance were identified in 10/32 isolates.

CONCLUSIONS

The EUCAST DD susceptibility method is more reliable than either CLSI or BMD for the detection of genotypically defined BLNAR resistance. However, accurate categorization of amoxicillin/clavulanate resistance remains problematic. Continuous and reproducible surveillance of resistance is needed; for this to be possible, robust susceptibility methods are required.

Genomic dynamics of species and mobile genetic elements in a prolonged blaIMP-4-associated carbapenemase outbreak in an Australian hospital

BACKGROUND

Hospital outbreaks of carbapenemase-producing organisms, such as blaIMP-4-containing organisms, are an increasing threat to patient safety.

OBJECTIVES

To investigate the genomic dynamics of a 10 year (2006-15) outbreak of blaIMP-4-containing organisms in a burns unit in a hospital in Sydney, Australia.

METHODS

All carbapenem-non-susceptible or MDR clinical isolates (2006-15) and a random selection of equivalent or ESBL-producing environmental isolates (2012-15) were sequenced [short-read (Illumina), long-read (Oxford Nanopore Technology)]. Sequence data were used to assess genetic relatedness of isolates (Mash; mapping and recombination-adjusted phylogenies), perform in silico typing (MLST, resistance genes and plasmid replicons) and reconstruct a subset of blaIMP plasmids for comparative plasmid genomics.

RESULTS

A total of 46/58 clinical and 67/96 environmental isolates contained blaIMP-4. All blaIMP-4-positive organisms contained five or more other resistance genes. Enterobacter cloacae was the predominant organism, with 12 other species mainly found in either the environment or patients, some persisting despite several cleaning methods. On phylogenetic analysis there were three genetic clusters of E. cloacae containing both clinical and environmental isolates, and an additional four clusters restricted to either reservoir. blaIMP-4 was mostly found as part of a cassette array (blaIMP-4-qacG2-aacA4-catB3) in a class 1 integron within a previously described IncM2 plasmid (pEl1573), with almost complete conservation of this cassette across the species over the 10 years. Several other plasmids were also implicated, including an IncF plasmid backbone not previously widely described in association with blaIMP-4.

CONCLUSIONS

Genetic backgrounds disseminating blaIMP-4 can persist, diversify and evolve amongst both human and environmental reservoirs during a prolonged outbreak despite intensive prevention efforts.

Increased detection of carbapenemase-producing Enterobacteriaceae on post-clean sampling of a burns unit's wet surfaces

Wet surface biofilms are a potential reservoir for multidrug-resistant Gram-negative organisms, including carbapenemase-producing Enterobacteriaceae (CPE). Recognition of environmental sources is important in reducing secondary patient transmission. We report the increased detection of blaIMP-4⁺ CPE in environmental samples from floor drains in burns unit shower rooms, when collected following cleaning as compared to pre-cleaning. We propose that disruption of biofilms during cleaning may account for the increased detection of multi-resistant organisms. The results highlight the role of the wet environment as an under-recognized potential source of CPE transmission. Environmental screening focusing on pre-cleaning samples alone will likely underestimate environmental contamination.

An international survey of cleaning and disinfection practices in the healthcare environment

BACKGROUND

Antimicrobial resistance has become an urgent global health priority. Basic hygiene practices and cleaning and disinfection of the hospital environment are key in preventing pathogen cross-transmission.

AIM

To our knowledge no studies have assessed the worldwide differences in cleaning and disinfection practices in healthcare facilities. The electronic survey described here was developed in order to evaluate differences in healthcare facility cleaning practices around the world.

METHODS

The International Society of Antimicrobial Chemotherapy (ISAC, formerly ISC), Infection Prevention and Control work group developed a survey with 30 multiple-choice questions. The questions were designed to assess the current cleaning practices in healthcare settings around the world.

FINDINGS

A total of 110 healthcare professionals, representing 23 countries, participated in the online survey. In 96% of the facilities a written cleaning policy was present. Training of cleaning staff occurred in 70% of the facilities at the start of employment. Cleaning practices and monitoring of these practices varied.

CONCLUSIONS

The survey enabled assessment and recognition of widely differing global practices in approaches to environmental cleaning and disinfection. Development of guideline recommendations for cleaning and disinfection could improve practices and set minimum standards worldwide.

Future trends in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infection: An in-depth review of newer antibiotics active against an enduring pathogen

Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a major public health problem. Vancomycin and teicoplanin have been in clinical use for several decades but their drawbacks are well described. In the last 10 years, several antibiotics have been made available for clinical use. Daptomycin and linezolid have been extensively used during this period. Other agents such as ceftaroline, ceftobiprole, dalbavancin, oritavancin, tedizolid and telavancin have been approved by regulatory agencies since 2009. Many others, such as the newer tetracyclines, fluoroquinolones, oxazolidinones and pleuromutilins, are in various stages of development. In addition, an ongoing multicentre trial is investigating the role of combination of vancomycin or daptomycin with β-lactam antibiotics. This review discusses the role of the newer antibiotics, reflecting the views of the 6th MRSA Consensus Conference meeting of the International Society of Chemotherapy MRSA Working Group that took place in 2016.

Clinical efficacy of β-lactam/β-lactamase inhibitor combinations for the treatment of bloodstream infection due to extended-spectrum β-lactamase-producing Enterobacteriaceae in haematological patients with neutropaenia: a study protocol for a retrospective observational study (BICAR)

INTRODUCTION

Bloodstream infection (BSI) due to extended-spectrum β-lactamase-producing Gram-negative bacilli (ESBL-GNB) is increasing at an alarming pace worldwide. Although β-lactam/β-lactamase inhibitor (BLBLI) combinations have been suggested as an alternative to carbapenems for the treatment of BSI due to these resistant organisms in the general population, their usefulness for the treatment of BSI due to ESBL-GNB in haematological patients with neutropaenia is yet to be elucidated. The aim of the BICAR study is to compare the efficacy of BLBLI combinations with that of carbapenems for the treatment of BSI due to an ESBL-GNB in this population.

METHODS AND ANALYSIS

A multinational, multicentre, observational retrospective study. Episodes of BSI due to ESBL-GNB occurring in haematological patients and haematopoietic stem cell transplant recipients with neutropaenia from 1 January 2006 to 31 March 2015 will be analysed. The primary end point will be case-fatality rate within 30 days of onset of BSI. The secondary end points will be 7-day and 14-day case-fatality rates, microbiological failure, colonisation/infection by resistant bacteria, superinfection, intensive care unit admission and development of adverse events.

SAMPLE SIZE

The number of expected episodes of BSI due to ESBL-GNB in the participant centres will be 260 with a ratio of control to experimental participants of 2.

ETHICS AND DISSEMINATION

The protocol of the study was approved at the first site by the Research Ethics Committee (REC) of Hospital Universitari de Bellvitge. Approval will be also sought from all relevant RECs. Any formal presentation or publication of data from this study will be considered as a joint publication by the participating investigators and will follow the recommendations of the International Committee of Medical Journal Editors (ICMJE). The study has been endorsed by the European Study Group for Bloodstream Infection and Sepsis (ESGBIS) and the European Study Group for Infections in Compromised Hosts (ESGICH).

Microsphaeropsis arundinis skin and soft tissue infection in renal transplant recipients: three case reports and a review of the literature

Microsphaeropsis arundinis, a dematiaceous mold, is emerging as a cause of skin and soft tissue infection in immunocompromised hosts. Diagnosis is challenging because of the difficulty in identifying Microsphaeropsis species morphologically and few data are available to guide optimal management. We report 3 renal transplant recipients with M. arundinis soft tissue infection, where the etiological agent was diagnosed using DNA sequencing, and who were successfully treated with prolonged courses of extended-spectrum triazole antifungal agents.

Consensus guidelines for the treatment of invasive mould infections in haematological malignancy and haemopoietic stem cell transplantation, 2014

Mould species represent the pathogens most commonly associated with invasive fungal disease in patients with haematological malignancies and patients of haemopoietic stem cell transplants. Invasive mould infections in these patient populations, particularly in the setting of neutropenia, are associated with high morbidity and mortality, and significantly increase the complexity of management. While Aspergillus species remain the most prevalent cause of invasive mould infections, Scedosporium and Fusarium species and the Mucormycetes continue to place a significant burden on the immunocompromised host. Evidence also suggests that infections caused by rare and emerging pathogens are increasing within the setting of broad-spectrum antifungal prophylaxis and improved survival times placing immunosuppressed patients at risk for longer. These guidelines present evidence-based recommendations for the antifungal management of common, rare and emerging mould infections in both adult and paediatric populations. Where relevant, the role of surgery, adjunctive therapy and immunotherapy is also discussed.

Persistent Rhodococcus equi infection in a renal transplant patient: case report and review of the literature

Rhodococcus equi is a pathogen that mainly causes infection in immunocompromised hosts. We report a case of relapsing R. equi pulmonary infection in a 57-year-old male renal transplant recipient who was treated with 12 months of antibiotics, adjunctive surgery, and a reduction in his immunosuppression. He suffered from relapsing disease, treatment-related complications, and ultimately died of Pneumocystis pneumonia. Case reports in the literature portray a good cure rate for transplant-related R. equi infections, with shorter durations of antibiotics. The case illustrates the difficulties in the management of R. equi infections. Forty cases from the literature were reviewed and compared in terms of epidemiology, location of infection, transplant type, immunosuppression used, treatment used, outcomes, and possible exposures.

A survey of medical staff attitudes to an antibiotic approval and stewardship programme

BACKGROUND

Antibiotic stewardship programmes (ASPs) are advocated to ensure appropriate antimicrobial use; with short-term evidence they may improve outcomes, limit adverse effects, encourage cost-effectiveness and reduce antibiotic resistance. At Concord Hospital, a 450-bed acute care hospital, we have used a telephone-based ASP for 15 years. There may be differences in attitudes to the ASP by prescribers, which may influence its long-term efficacy.

METHOD

A 40-item self-administered questionnaire was sent to 190 junior and 250 specialist medical staff. We aimed to elicit medical staff attitudes to the ASP's utility, educational value, effect on patient care and ease of use.

RESULTS

One hundred and sixty-four completed questionnaires were returned. Most (82%, 95% confidence interval (95%CI) 75-87%) clinicians had used the ASP, 98% of whom believed it to be a reasonable system. Most staff (85%, 95%CI 79-90%) believed that seeking approval made teams think carefully about antibiotic choice, agreed it provided helpful advice (91%, 95%CI 85-95%) and that the approval system provided useful advice and was educational (88%, 95%CI 81-92%). The ASP was felt time-consuming and detracting from clinical duties by 33% (95%CI 26-41%), while 10% (95%CI 5.8-15.7%) believed it undervalued intuition and experience. Few (19%, 95%CI 13-25%, P < 0.0001) clinicians believed it infringed their autonomy. The advice given through the ASP was believed by most (89%, 95%CI 81-92%) to improve patient outcomes.

CONCLUSION

The ASP was surprisingly well supported by all levels of staff, and reinforced the benefits of maintaining an ASP policy.

Point-of-care urinary pneumococcal antigen test in the emergency department for community acquired pneumonia

BACKGROUND

Streptococcus pneumoniae is the most common cause of community-acquired pneumonia (CAP). Early diagnosis would allow more directed therapy and confidence in appropriate treatment for a majority of patients. The BinaxNOW pneumococcal urinary antigen (PNAG) test has been evaluated at laboratory level and is easy to perform and interpret, but its use as a point-of-care test has not been evaluated. A study was undertaken to assess whether PNAG testing can be reliably performed and interpreted by staff in an adult emergency department and whether rapid results influence initial treatment decisions.

METHODS

Community-living adult patients presenting to the emergency department with clinical and radiological findings of pneumonia had PNAG testing performed on the same sample in both the emergency department and the microbiology laboratory in a blinded fashion. Accuracy and turnaround time were assessed. Diagnostic yield was compared with routine culture methods.

RESULTS

Fifty-nine patients were enrolled of whom nine (15%) had positive PNAG tests. These included three culture-proven cases and six additional cases. There was 98% concordance between emergency department and laboratory results. Turnaround time was significantly shorter when tested in the emergency department (median 2 h 39 min vs 19 h 40 min). Antibiotic prescribing was not influenced by results in this small sample.

CONCLUSIONS

PNAG diagnosis of pneumococcal pneumonia can be accurately performed as a point-of-care test by emergency department clinical staff. Without specific efforts to achieve early urine collection, the timeframe of testing will frequently fall outside the 4-hour patient stay of a UK emergency department and may be more appropriately considered as a test for the medical admissions unit in this setting. Sensitivity is at least equal to conventional culture methods and the result is available rapidly enough to potentially influence treatment decisions, a strategy that warrants further investigation.

Tuberculous cranial pachymeningitis

We describe two immunocompetent patients with tuberculous cranial pachymeningitis. Both patients underwent biopsy after focal dural thickening was identified on MRI. Histopathologic examination of tissue revealed necrotizing granulomatous inflammation. PCR for Mycobacterium tuberculosis DNA was negative on CSF but positive on tissue. Both patients responded to antituberculous therapy. Although uncommon as a cause of cranial pachymeningitis, tuberculosis should be considered, since it responds well to treatment.

Laboratory cross-contamination of Mycobacterium tuberculosis: an investigation and analysis of causes and consequences

BACKGROUND

The misdiagnosis of Mycobacterium tuberculosis infection has many ramifications. These include medical and psychological implications for patients and their families and financial and public health implications for health-care institutions. Microbiology laboratory procedures should minimize the possibility of laboratory cross-contamination of specimens and maximize the ability to recognize a cluster of false-positive cultures. Newer molecular typing methods provide rapid, accurate and effective means of identifying false-positive M. tuberculosis cultures.

AIMS

To investigate a cluster of patients with positive M. tuberculosis cultures that were processed in the mycobacteriology laboratory on the same day.

METHODS

Five patients' medical records and radiology results were reviewed to determine whether the cases were epidemiologically linked and whether there was clinical suspicion of tuberculosis. Restriction fragment length polymorphism (DNA fingerprinting) was performed using repetitive elements IS6110 and pTBN12. Laboratory processing procedures were analysed.

RESULTS

On the basis of DNA fingerprinting using IS6110, the isolates from all five patients were identical. Molecular typing using pTBN12 was performed on four of the five isolates. All four had identical patterns. There was no epidemiological link between the patients. At least three (and probably four) of the five patients were misdiagnosed with tuberculosis.

CONCLUSION

Microbiology laboratories should ensure that appropriate methodologies are in place to avoid cross-contamination of specimens. Clinicians need to critically interpret any positive laboratory result, especially in an unlikely clinical setting.

Case report. Successful treatment of cutaneous Paecilomyces lilacinus infection with oral itraconazole in an immune competent host

A 59-year-old woman presented to us with an eight-month history of Paecilomyces lilacinus soft tissue infection. She was treated with a six-month course of oral itraconazole. The lesion resolved fully without the need for adjunctive surgery. Susceptibility testing confirmed susceptibility to itraconazole. This is the second case of confirmed P. lilacinus soft tissue infection in an immunocompetent host treated with oral itraconazole alone.

Multi-drug resistant Pseudomonas aeruginosa outbreak in a burns unit--an infection control study

A newly introduced, multi-drug resistant (MDR) strain of Pseudomonas aeruginosa was isolated from four patients admitted to the Concord Hospital Burns Unit (BU) between December 1997 and March 1998. It was the cause of recurrent episodes of bacteraemia in two. This strain was resistant in vitro to gentamicin, piperacillin and ciprofloxacin. The isolates were confirmed as a clonal strain by pulse field gel electrophoresis (PFGE). Multiple environmental swabs were taken to search for an environmental reservoir, but no source was identified. Random cultures of staff members' hands failed to demonstrate ongoing carriage. In the absence of a demonstrable point source for the outbreak, direct cross-transmission patient to patient, via transient staff hand contamination, was the most likely route of infection. Following study commencement no new cases of infection with the MDR strain were detected. It would appear that the infection cycle has been interrupted, and the outbreak terminated following the discharge of the last infected patient from the BU. Contamination of a neutral detergent in the BU with Klebsiella oxytoca was detected incidentally during environmental surveillance. A potential hospital-wide outbreak was averted.

Multisite regional telephone care

A multisite, regional telephone-care program staffed by advance practice and critical care nurses has improved patient care and reduced unnecessary clinic and emergency room visits. It allows patients to access the health care system and receive expert advice through the use of the telephone, 24 hours per day, 7 days per week. Computerized patient medical records from eight hospitals and 31 clinics are available to a registered nurse so that informed decisions can be made. The RN records the patient's concern and intervention directly into the patient's medical record, which is transmitted to the primary care provider in real time.

Disseminated mucormycosis due to Saksenaea vasiformis in an immunocompetent adult

A case of disseminated infection due to Saksenaea vasiformis in a previously well adult male is presented. The clinical presentation was that of septic shock with a distinctive rash. At postmortem, endocarditis and widespread dissemination were evident.

Rapid ATM-dependent phosphorylation of MDM2 precedes p53 accumulation in response to DNA damage

The p53 tumor-suppressor protein, a key regulator of cellular responses to genotoxic stress, is stabilized and activated after DNA damage. This process is associated with posttranslational modifications of p53, some of which are mediated by the ATM protein kinase. However, these modifications alone may not account in full for p53 stabilization. p53's stability and activity are negatively regulated by the oncoprotein MDM2, whose gene is activated by p53. Conceivably, p53 function may be modulated by modifications of MDM2 as well. We show here that after treatment of cells with ionizing radiation or a radiomimetic chemical, but not UV radiation, MDM2 is phosphorylated rapidly in an ATM-dependent manner. This phosphorylation is independent of p53 and the DNA-dependent protein kinase. Furthermore, MDM2 is directly phosphorylated by ATM in vitro. These findings suggest that in response to DNA strand breaks, ATM may promote p53 activity and stability by mediating simultaneous phosphorylation of both partners of the p53-MDM2 autoregulatory feedback loop.

Multicenter evaluation of the Abbott LCx Mycobacterium tuberculosis ligase chain reaction assay

Four Australian hospital laboratories evaluated the performance of the Abbott LCx Mycobacterium tuberculosis assay with 2,347 specimens (2,083 respiratory and 264 nonrespiratory specimens) obtained from 1, 411 patients. A total of 152 specimens (6.5%) were culture positive for Mycobacterium tuberculosis complex (MTBC); of these, 79 (52%) were smear positive. After resolution of discrepant data, the overall sensitivity, specificity, and positive and negative predictive values for the LCx assay were 69.7, 99.9, 99.1, and 97.7% respectively. For smear-positive respiratory specimens that were culture positive for MTBC, the values were 98.5, 100, 100, and 98.4%, respectively, while the values for smear-negative respiratory specimens were 41.5, 99.9, 96.4, and 98%, respectively. Relative operating characteristic curves were constructed to demonstrate the relationship between sensitivity and specificity for a range of possible cutoff values in the LCx assay. These graphs suggested that the assay sensitivity for respiratory samples could be increased from 70.2 to 78.6%, while the specificity would be reduced from 99.9 to 99.4% by inclusion of a grey zone (i.e., LCx assay values of between 0.2 and 0.99). An algorithm is presented for the handling of specimens with LCx assay values within this grey zone.

Fusidic acid in bone and joint infections

The prominence of staphylococci as the causative agent in bone and joint infections suggests that fusidic acid (FA) has a potentially important role in their treatment. FA has been studied in a broad range of orthopaedic infections, mostly in combination with other antimicrobials. For susceptible organisms, particularly Staphylococcus aureus, it has demonstrable efficacy in acute osteomyelitis, chronic osteomyelitis, specialised forms of osteomyelitis such as calcaneal and vertebral infection, septic arthritis, prosthetic and other device-related infections. A small number of studies have also examined the use of FA alone for the treatment of bone infections, with evidence of good efficacy, as well as the local application of FA in plaster-of-Paris (POP) beads, or incorporated into bone cement, again with promising results. Further studies are required to confirm the efficacy of FA in the treatment of orthopaedic infections caused by methicillin-resistant strains of S. aureus.

Outcome and complications of temporary haemodialysis catheters

BACKGROUND

The use of temporary haemodialysis catheters is often complicated by mechanical or infectious complications. Risk factors for these complications and optimal management to reduce their incidence are largely unknown.

METHODS

We conducted a prospective study of 105 haemodialysis catheters (79 subclavian, 26 jugular) inserted in 52 patients in order to identify patient outcomes and to analyse the effect of patient and catheter factors on the incidence of infectious complications by multivariate analysis.

RESULTS

Fifty-nine per cent of catheters were removed for a suspected complication. Catheter-related bacteraemia (CRB) was diagnosed in 17 catheters (16%), giving a bacteraemia rate of 6.5 episodes per 1000 catheter days. Subgroup analysis revealed a higher risk of CRB with the use of the internal jugular compared with the subclavian site (hazard ratio 3.97, P=0.02). Age, diabetes or catheter exchange over a guidewire did not alter the risk of CRB. The cumulative risk of developing CRB increased in a linear fashion as the period of catheterization increased. Exit-site infection was the cause for removal in eight catheters (8%). Although the number of exit-site infections was small, the risk of exit-site infection was increased in diabetic patients (hazard ratio 10, P=0.03) and the jugular position (hazard ratio 6.5, P=0.01) but not by age or catheter exchange over a guidewire. Staphylococcus aureus and coagulase-negative staphylococcus accounted for all proven episodes of CRB. Exit-site infection was associated with a mixture of Gram-positive and Gram-negative organisms.

CONCLUSIONS

Temporary haemodialysis catheters have a high failure rate associated with a significant rate of complications. Use of the internal jugular site is associated with a significantly higher risk of infectious complications and methods to reduce this risk should be considered if this site is used.

Cat scratch disease diagnosed by polymerase chain reaction in a patient with suspected tuberculous lymphadenitis

We present a patient diagnosed as having tuberculous lymphadenitis after lymph node biopsy and referred for tuberculous therapy. On review, because of recent cat exposure, she was tested for cat scratch disease (CSD), but serological tests for Bartonella henselae were negative. However, the diagnosis of CSD was confirmed, and tuberculosis excluded, by polymerase chain reaction techniques. This case serves as a reminder that CSD may mimic tuberculosis histologically and that sensitive molecular diagnostic tests are available.

The independent evolution of resistance to ciprofloxacin, rifampicin, and fusidic acid in methicillin-resistant Staphylococcus aureus in Australian teaching hospitals (1990-1995). Australian Group for Antimicrobial Resistance (AGAR)

Methicillin-resistant Staphylococcus aureus (MRSA) is endemic in teaching hospitals in eastern Australian states, with prevalence rates averaging 25-30% of all S. aureus. Between 1990 and 1995, 1467 non-duplicate MRSA isolates from clinically infected sites were tested in Sydney, Melbourne, and Brisbane as part of a national survey of staphylococcal susceptibility. We reviewed the differing evolution of resistance to ciprofloxacin, rifampicin, and fusidic acid. Despite similarities in community and hospital antibiotic use and MRSA prevalence rates, trends in resistance to the oral antibiotics in these cities have progressed independently of each other. In the 1995 survey in individual hospitals in Melbourne, 16-24% of strains were ciprofloxacin-resistant, compared with 80-100% in Sydney and 30-44% in Brisbane. There was great diversity of phage type patterns for ciprofloxacin-resistant strains, suggesting heterogeneous development of resistance. Rifampicin resistance was more closely associated with distinct dominant epidemic phage types, common to institutions in the same city, but without spread to the other cites. Between 1990 and 1995, these comprised 30-60% of all MRSA in Brisbane, compared with 5-10% in Melbourne and < 25% in Sydney. Fusidic acid resistance was uncommon and sporadic (< 5%), and was distributed equally between methicillin-resistant and methicillin-susceptible strains. Resistance to the oral agents in MRSA is due to a complex mix of antibiotic selection pressures and cross-infection with local and epidemic strains in closely related institutions. Each of these mechanisms can predominate, dependent on local factors and the antibiotics used.

Candidaemia in an Australian teaching hospital: relationship to central line and TPN use

We performed a retrospective review of patient case records to identify risk factors for candidaemia and to assess incidence, management and outcome of candidaemia in an Australian teaching hospital. Between January 1994 and June 1996, 38 cases of candidaemia were identified. The incidence was 0.74 per 1000 admissions of 24 h duration, and 1.54 per 1000 admissions of 5 days or more. The mortality rate was 34%, with eight of 13 (62%) of these deaths attributable to candidaemia. Risk factors included underlying gastrointestinal disease (66%) and recent abdominal surgery (61%), while recent broad spectrum antibiotic use was a contributing factor in 95%. Twenty-nine patients (76%) had a vascular access device in situ at time of detection. This was the apparent source of candidaemia in 28 (97%). Twenty-six (90%) were being used for TPN administration. Of patients receiving TPN, 5.2% developed candidaemia. Standard central venous catheters (CVC) were present in 21 patients (55%), having been in situ for an average of 12.7 days. Eighteen (86%) had been in situ for 7 days or more. Management involved removal of any implicated intravascular device. Thirty of 33 early survivors received antifungal chemotherapy. Therapy with amphotericin B, fluconazole alone or amphotericin B followed by fluconazole was equally effective. Concurrent corticosteroid use and neutropaenia contributed to increased mortality. Candidaemia is not benign. Policies regarding regular changing of central lines, especially in the setting of TPN administration and control of broad spectrum antibiotic use are appropriate measures aimed to reduce incidence. Management involves removal of implicated lines and antifungal chemotherapy. Pre-emptive therapy for candida infection should be considered in selected patients with the likelihood of TPN-related central line sepsis. Fluconazole is an effective alternative to amphotericin B in non-neutropenic patients.

Staphylococcal bacteraemia: the hospital or the home? A review of Staphylococcus aureus bacteraemia at Concord Hospital in 1993

AIMS

To examine the risk factors for, and the complications and mortality of, Staphylococcus aureus bacteraemia.

METHODS

A retrospective case review of patients with S. aureus bacteraemia in 1993 diagnosed at the Concord Repatriation General Hospital, Sydney.

RESULTS

Of 104 cases reviewed, 32 were due to methicillin resistant S. aureus (MRSA), 73 were due to methicillin sensitive S. aureus (MSSA) and one was a dual infection. Twenty-eight of the bacteraemias were community-acquired, including one case of MRSA, and 76 were hospital-acquired; 38% had an implanted prosthetic device or graft. The average age (68 years), incidence of underlying diseases and hospitalisation in the past month (26%) did not differ between MRSA and MSSA groups. MRSA was more likely in patients with recent broad-spectrum antibiotic use (53% vs 0, p < .01). Vascular access was the commonest source of sepsis (61%) but in community-acquired cases the source was unknown in 50%. Use of central line access was more predictive of MRSA infection (75% vs 49%, p = .018). In hospital-acquired infection, MRSA sepsis occurred later in the course of the admission (26 days vs eight days, p < .01). Directly attributable mortality was highest in MRSA and community-acquired MSSA infection (9% and 11%) compared with hospital-acquired MSSA infection (1%).

CONCLUSIONS

Nosocomial S. aureus bacteraemia, particularly MRSA, is a major source of preventable morbidity, which could be addressed by improved infection control of MRSA, antibiotic use and attention to central line catheter use.

The Etest for antimicrobial susceptibility testing of Bartonella henselae

The in-vitro susceptibility of 10 isolates of Bartonella henselae was assessed using the Etest. The organisms, one reference human strain and nine feline isolates, were grown on chocolate agar and the Etests read at days 5, 8 and 11. Six antibiotics, erythromycin, azithromycin, doxycycline, ciprofloxacin, rifampicin and vancomycin were evaluated. The results correlated well with published results using agar dilution. The results confirmed the high in-vitro susceptibility of B. henselae to erythromycin, azithromycin, doxycycline and rifampicin and to a lesser extent ciprofloxacin. The majority of isolates were resistant to vancomycin. Although in-vitro results of B. henselae susceptibility testing may not necessarily correlate with clinical response, the Etest may be a simpler way for laboratories to monitor for the development of resistance particularly in the setting of relapsing infection.

Prevalence of Bartonella henselae bacteremia, the causative agent of cat scratch disease, in an Australian cat population

In order to determine the prevalence of Bartonella henselae becteremia in an Australian cat population we examined blood cultures on a group of Sydney cats. Cats referred to the Concord Animal Hospital for euthanasia were selected randomly for blood culture and serum sampling. Blood samples were lysed and centrifuged and then cultured for up to five weeks. Suspicious colonies were identified biochemically as probable B. henselae. Selected isolates were confirmed as B. henselae using the polymerase chain reaction. Of the cats accrued throughout Sydney, 27/77 (35%) were culture positive for B. henselae, of these 24/59 (40%) were feral cats and 3/18 (16%) were domestic. Most cats in the study were younger than one year (mean 9.9 months). Our study demonstrates that bacteremia with B. henselae is common in the metropolitan cat population and suggests that it is particularly prevalent among feral animals. By contrast Cat Scratch Disease (CSD) is a relatively uncommon clinical diagnosis in the Australian population. Explanations for this discrepancy may include poor transmission, low bacterial virulence and underdiagnosis. It is possible that feral animals are a greater potential risk source for this infection than domestic cats.

Evaluation of CHROMagar Orientation for differentiation and presumptive identification of gram-negative bacilli and Enterococcus species

A new chromogenic plate medium, CHROMagar Orientation, was evaluated for use in the differentiation and presumptive identification of gram-negative bacilli and Enterococcus species by a multipoint inoculation (replicator) technique. In this study, 1,404 gram-negative bacilli and 74 enterococcal isolates were tested on CHROMagar Orientation. Six control American Type Culture Collection strains were also included with the testing to ensure quality control of the media. Of the Escherichia coli isolates (n = 588) tested, 99.3% produced a pink-to-red color. Only in four isolates that were O-nitrophenyl-beta-D-galactopyranoside (ONPG) negative did this result differ. Proteus mirabilis and P. vulgaris were well differentiated on this medium. P. mirabilis (n = 184) produced a clear colony with diffusible brown pigment around the periphery. By contrast, 15 of 16 P. vulgaris isolates produced bluish-green colonies with a slight brown background. All Aeromonas hydrophila isolates (n = 26) tested produced clear to pink colonies at 35 to 37 degrees C. This colony color changed to blue after 2 to 3 h of incubation at room temperature. A. hydrophila exhibited stronger color and better growth at 30 degrees C. Serratia marcescens (n = 29) demonstrated an aqua blue color that deepened to a darker blue when exposed to room temperature. All enterococcal isolates (n = 74) resulted in a blue color and gave pinpoint colonies on purity subcultures at 35 to 37 degrees C after 18 h of incubation. Similarity in color resulted in failure to discriminate accurately between Klebsiella, Enterobacter, and Citrobacter species. However, these species could be readily differentiated from other members of the family Enterobacteriaceae. Pseudomonas aeruginosa (n = 151) was easily differentiated from members of the Enterobacteriaceae but was less easily distinguishable from other gram-negative nonmembers of the Enterobacteriaceae. The medium was found to facilitate easy visual detection of mixed bacterial isolates in culture. When used in a replicator system, it easily detected mixed growths of organisms which may have otherwise led to false antibiotic susceptibility results. These mixed growths were not obvious on the routine susceptibility testing medium (Isosensitest).

Managing HIV. Part 5: Treating secondary outcomes. 5.15 HIV and non-tuberculous mycobacterial infection

About one in three patients with advanced immune deficiency will develop disseminated MAC infection. This incidence can be reduced with prophylactic drug therapy, and established infections can be effectively treated, with improved quality of life and lengthened survival.

Comparison of two commercial enzyme immunoassays with cytotoxicity assay and culture for the diagnosis of Clostridium difficile related diarrhea

184 stool samples were analysed for the presence of Clostridium difficile and toxins using the Meridian Premier Toxin A and TechLab Tox-A EIA kits, selective culture and cytotoxin assay. Of the 184 samples 36 stools tested positive for cytotoxin. In comparison the sensitivity and specificity of the EIAs and culture were as follows: Meridian, 72 and 87, TechLab, 64 and 95, and selective culture, 83 and 96%, respectively. The positive predictive values and negative predictive values for the various methods were: Meridian, 58 and 93, TechLab, 77 and 92, and selective culture, 83 and 96%, respectively. Discrepant results to those obtained by cytotoxicity assay were encountered with both EIA kits evaluated and less so by culture. In this study direct isolation of Clostridium difficile from stool samples most closely paralleled the findings of the "gold standard" cell line cytotoxicity assay. It appears that a single test for the determination of Clostridium difficile disease is adequate, although a second method improves the predictability of the diagnosis. Direct culture of feces provided a reliable secondary procedure to cytotoxicity assay. The EIAs were simple to use, labour efficient and provided a rapid result. However the lack of sensitivity and relative expense did not justify their routine use in our laboratory.