Development and piloting of a prevention assessment and response tool for healthcare-associated Staphylococcus aureus bloodstream infection (the SAB-PART Study) using a Delphi method

BACKGROUND

Healthcare-associated Staphylococcus aureus bloodstream infection (HA-SAB) causes preventable harm in hospitalized patients. Currently, there is no standardized method available to review HA-SAB events in order to identify and target preventable risks requiring action at an organizational level.

AIM

To develop a tool to classify SAB events, and the necessary response actions, according to the degree of preventability.

METHODS

Following a literature review, a tool was developed. Consensus feedback and development of the tool was sought from experts (N = 11) in healthcare-associated infection surveillance using a Delphi technique. The completed tool was retrospectively applied to HA-SAB events (N = 43) that occurred at a large healthcare organization.

FINDINGS

Survey completion rates were high (91-100%). Clinicians' poor adherence to infection prevention practices and lack of engagement with feedback processes was established as the key modifiable element. A second key theme was the need for structured and detailed response actions. This feedback was incorporated into the tool and refined until consensus on all elements was achieved. Pilot application of the tool found that 56% of HA-SAB events were highly or possibly preventable; modifiable factors for HA-SAB prevention were not present in the remainder of cases.

CONCLUSION

A prevention assessment and response tool was successfully developed via a consensus method to assist organizations in investigating and responding to individual cases of HA-SAB and identify future priority areas for SAB reduction strategies. Wider use of the tool with routine surveillance activities is required to evaluate impact upon infection prevention programmes and patient outcomes.

Mobile phones and computer keyboards: unlikely reservoirs of multidrug-resistant organisms in the tertiary intensive care unit

Few studies have used molecular epidemiological methods to study transmission links to clinical isolates in intensive care units. Ninety-four multidrug-resistant organisms (MDROs) cultured from routine specimens from intensive care unit (ICU) patients over 13 weeks were stored (11 meticillin-resistant Staphylococcus aureus (MRSA), two vancomycin-resistant enterococci and 81 Gram-negative bacteria). Medical staff personal mobile phones, departmental phones, and ICU keyboards were swabbed and cultured for MDROs; MRSA was isolated from two phones. Environmental and patient isolates of the same genus were selected for whole genome sequencing. On whole genome sequencing, the mobile phone isolates had a pairwise single nucleotide polymorphism (SNP) distance of 183. However, >15,000 core genome SNPs separated the mobile phone and clinical isolates. In a low-endemic setting, mobile phones and keyboards appear unlikely to contribute to hospital-acquired MDROs.

Mucormycete infection or colonisation: experience of an Australian tertiary referral centre

Mucormycosis is associated with significant morbidity and mortality. We reviewed patients with mucormycete isolated at Alfred Health, Australia. A retrospective review of 66 patients with mucormycete(s) identified, between 1 April 2008 and 30 June 2014. Baseline demographic, microbiological, radiological, treatment/outcome data were recorded. Site of isolation was sinopulmonary in 77% and skin/soft tissue in 21%. A total of 32% of cases were proven-IFD, 12% probable-IFD and 56% were defined as no-IFD (or colonisation). Rhizopus spp. was identified in 48%. Comparing probable/proven-IFD with no-IFD/colonisation, more patients were postallogeneic stem cell transplantation (28% vs. 0%, P < 0.01) and were receiving immunosuppressive therapy (59% vs. 24%, P < 0.01) including prednisolone >20 mg daily (24% vs. 5%, P = 0.04). A total of 93% of patients with proven/probable IFD received treatment while 30% of no-IFD/colonisation were treated. A total of 72% of patients with proven/probable IFD and 92% of those with colonisation had no further mucormycete isolated. Thirty day mortality was higher in the proven/probable-IFD cohort (24%) compared with no-IFD/colonisation (3%) (P = 0.02). Mucormycosis remains uncommon, with 56% of cases not associated with clinical infection. Immunosuppressive therapy remains strongly associated with mucormycosis. Mortality remains high in those with proven/probable IFD.

Clinical utility of panfungal polymerase chain reaction for the diagnosis of invasive fungal disease: a single center experience

The role of panfungal polymerase chain reaction (PCR) assays for diagnosis of invasive fungal disease (IFD) is inadequately defined. We describe the use of an internal transcribed spacer 1 (ITS-1) region-directed panfungal PCR in this context at a tertiary referral transplant center. A retrospective review of patients at Alfred Health, Melbourne, Australia (2009-2014) who had clinical samples referred for panfungal PCR testing was conducted. Baseline patient characteristics, antifungal drug history, fungal culture/histopathology, and radiology results were recorded. For bronchoalveolar lavage (BAL) fluid samples, identification of a fungus other than a Candida spp. was defined as a potential pathogen.Of 138 panfungal PCR tests (108 patients), 41 (30%) were positive for a fungal product. Ninety-seven percent (134/138) of specimens were from immunocompromised hosts. Thirteen percent (19/138) of panfungal PCR positive results were for potential pathogens and potential pathogens were detected more frequently in tissue as compared with BAL (12/13 vs. 6/26; P = .0001). No positive panfungal PCR results were obtained from CSF specimens. If histopathology examination was negative, panfungal PCR identified a potential pathogen in only 12% (11/94) of specimens. For the 20 culture negative/histopathology positive specimens, diagnosis of IFD to causative species level by panfungal PCR occurred in 35% (6/20).Sterile site specimens, in particular tissue, were more frequently panfungal PCR positive for potential pathogens than BAL. The utility of panfungal PCR appears greatest in tissue specimens, as an adjunct to histopathology to improve diagnostic sensitivity and specificity. Based on the results of this study we are now only testing tissue specimens by panfungal PCR.

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.

Candida infective endocarditis

Candida infective endocarditis (IE) is uncommon but often fatal. Most epidemiologic data are derived from small case series or case reports. This study was conducted to explore the epidemiology, treatment patterns, and outcomes of patients with Candida IE. We compared 33 Candida IE cases to 2,716 patients with non-fungal IE in the International Collaboration on Endocarditis-Prospective Cohort Study (ICE-PCS). Patients were enrolled and the data collected from June 2000 until August 2005. We noted that patients with Candida IE were more likely to have prosthetic valves (p < 0.001), short-term indwelling catheters (p < 0.0001), and have healthcare-associated infections (p < 0.001). The reasons for surgery differed between the two groups: myocardial abscess (46.7% vs. 22.2%, p = 0.026) and persistent positive blood cultures (33.3% vs. 9.9%, p = 0.003) were more common among those with Candida IE. Mortality at discharge was higher in patients with Candida IE (30.3%) when compared to non-fungal cases (17%, p = 0.046). Among Candida patients, mortality was similar in patients who received combination surgical and antifungal therapy versus antifungal therapy alone (33.3% vs. 27.8%, p = 0.26). New antifungal drugs, particularly echinocandins, were used frequently. These multi-center data suggest distinct epidemiologic features of Candida IE when compared to non-fungal cases. Indications for surgical intervention are different and mortality is increased. Newer antifungal treatment options are increasingly used. Large, multi-center studies are needed to help better define Candida IE.

A longitudinal study of Acinetobacter in three Australian hospitals

Acinetobacter has recently risen in prominence as a nosocomial pathogen, particularly due to increasing antibiotic resistance. The aim of this study was to describe changes in rates and antibiotic susceptibility patterns of Acinetobacter in three Melbourne hospitals. This was a retrospective review of microbiology records over five years. The rates of new clinical isolates of Acinetobacter per 10 000 discharges per quarter were calculated. Other information collected included antibiotic susceptibility patterns, age, gender, length of stay and ward [intensive care unit (ICU) or non-ICU]. Rates increased substantially at two hospitals, but not at the third. Increasing numbers at one hospital were associated with antibiotic resistance. Most first isolates were identified while the patient was in the ICU. Many isolates were from respiratory specimens, although a significant proportion was from blood. This study documents the establishment of Acinetobacter as a nosocomial pathogen in two Melbourne hospitals and serves as a warning for the future.

Strongyloides stercoralis: risks posed to immigrant patients in an Australian tertiary referral centre

BACKGROUND

Strongyloides stercoralis is a nematode human parasite with a global prevalence that is able to maintain a prolonged infestation by means of its autoinfective life cycle. Immunosuppression may result in a life-threatening hyperinfection syndrome. Recent changes in migration have resulted in the arrival of many immigrants from endemic areas. As to whether physicians are alert to the risks of strongyloidiasis in these patient groups is unclear. The aim of the study was to assess the risks posed by chronic strongyloidiasis in patients presenting to a tertiary referral centre and the need for screening of immigrant patients before immunosuppression.

METHODS

The study comprised a retrospective review of cases of strongyloidiasis presenting to the Alfred Hospital, Melbourne. Thirty-three cases were diagnosed by either positive serology or faecal microscopy between January 1998 and January 2005. The medical records for 29 cases were examined with regard to demographics, clinical features and complications.

RESULTS

Two major groups were identified: immigrants (17) and returned travellers (11). Six immigrants, but no returned traveller, developed a hyperinfective syndrome. Five immigrants received immunosuppressive therapies before developing symptoms of hyperinfection and this was complicated by life-threatening sepsis in two patients. Diagnosis was frequently delayed in the immigrant group who were significantly more likely to present with respiratory symptoms. Four immigrants and two returned travellers were treated with corticosteroids for symptoms that were probably related to larval migration.

CONCLUSION

Before giving immunosuppressive therapies, patients with a history of potential exposure must be investigated for strongyloidiasis and consideration given to empirical treatment.

Rate of nosocomial transmission of vancomycin-resistant enterococci from isolated patients

To evaluate an isolation policy for patients colonised with vancomycin-resistant enterococci (VRE), we instituted active surveillance for transmission to uncolonised patients. Surveillance rectal swabs were taken and pulsed-field gel electrophoresis was performed on positive isolates. VRE transmission with an identical genotype occurred in 5 patients, giving a transmission rate of 3.7 per 1000 patient days, or 1 patient per ward each week. The present study provides a baseline for -assessment of VRE transmission and will be useful in evaluation of the effectiveness of infection control interventions.

Control of endemic MRSA-what is the evidence? A personal view

Although there is extensive literature on the control of MRSA, when that concerning epidemics is excluded, only a limited amount remains regarding the control of endemic MRSA. Several guidelines have been recently published recommending stringent control measures, which are often suggested based on their success in controlling MRSA outbreaks in hospitals with few MRSA or in containing MRSA cases introduced into a hospital with no MRSA. In these settings, multiple measures are usually introduced with apparently successful results. However, results may not be generalizable to other settings and we do not know the minimum effective measures required for MRSA containment. This paper aims critically to review the literature to determine whether evidence exists for the value of the infection control measures that are widely recommended in the endemic setting. Much of this literature is based on observational studies, with few randomized, controlled trials having been conducted. More well-designed studies are required before many of the principles on which we build infection control programmes can be regarded as evidence based.

Risk factors for acquisition of methicillin-resistant Staphylococcus aureus (MRSA) by trauma patients in the intensive care unit

In a previous study in the intensive care unit (ICU) of the Alfred Hospital, Melbourne, Australia, it was demonstrated that trauma patients were at particular risk of becoming colonized by methicillin-resistant Staphylococcus aureus (MRSA). We examined risk factors for MRSA acquisition in these patients using a cohort study comparing the 31 patients who acquired MRSA with 65 who did not. Data collected included ICU length of stay (LOS), mechanism of trauma, site of injury, type of surgery, trauma severity and antibiotic usage. Odds ratios (OR) were determined and adjusted for LOS. LOS in the ICU was a significant univariate predictor of MRSA acquisition (OR 13.7). When adjusted for LOS, mechanism of trauma (OR 10.4), laparotomy (OR 6.3) and administration of ticarcillin/clavulanic acid (OR 4.5) or glycopeptides (OR 5.9) remained significant. We confirmed our previous finding that LOS was associated with MRSA acquisition. Receipt of antibiotics correlated with reported literature. Novel associations were road trauma as a mechanism and laparotomy.

Hospital infection control in Australia

Australia is a large country divided into six states and two territories, each of which has infection control programmes. This paper looks at the organization of infection control in Australia, as well as describing the national bodies involved and recent state initiatives in infection control.

Chronic relapsing salmonella osteomyelitis in an immunocompetent patient: case report and literature review

We present the first case of Salmonella virchow causing a relapsing bone infection at the same site 12 years apart in an otherwise healthy patient. Chronic relapsing osteomyelitis caused by a zoonotic salmonella may become increasingly important in view of the increased incidence of zoonotic salmonella infections. Based on this case, we recommend 3 months of therapy with a quinolone when treating a chronic relapsing zoonotic salmonella osteomyelitis.

Post-discharge surgical wound infection surveillance in a provincial hospital: follow-up rates, validity of data and review of the literature

BACKGROUND

Numerous studies suggest that many surgical site infections (SSI) come to light only after discharge from hospital. With increasing trends towards shorter length of stay and ambulatory day surgery, post-discharge surveillance may become necessary for all infection control programs, but the methodology has yet to be validated and standardized. The overall aim of the present study was to examine the impact of effective post-discharge SSI follow up on the overall SSI rate.

METHODS

A prospective targeted surveillance programme of 1291 surgical procedures was conducted at St John of God Health Care Geelong using the standardized National Nosocomial Infections Surveillance (NNIS) METHOD: Questionnaires were sent to surgeons and the results rigorously chased up. Factors giving rise to high follow-up rates and the relationship between follow up, attrition bias and validity of data were explored using a literature search.

RESULTS

A post-discharge follow-up rate of 98.7% was achieved. When the post-discharge data were included, the overall SSI rate (6.0% (95% CI: 4.7-7.4)) was more than double that in hospital (2.7% (95% CI: 1.9-3.8)).

CONCLUSIONS

An effective post-discharge follow-up programme significantly increased the SSI rate. From the authors' experience and a literature survey, possible ways to achieve high follow-up rates were suggested. It was also recommended that professional and regulating bodies in Australia be encouraged to standardize methodology and set minimum follow-up rates for post-discharge SSI surveillance. Increasing use of computerized hospital database systems for automated data gathering and processing should make this more practicable.

Comparison of a multiplex reverse transcription-PCR-enzyme hybridization assay with conventional viral culture and immunofluorescence techniques for the detection of seven viral respiratory pathogens

A multiplex reverse transcription-PCR-enzyme hybridization assay (RT-PCR-EHA; Hexaplex; Prodesse Inc., Waukesha, Wis.) was used for the simultaneous detection of human parainfluenza virus types 1, 2, and 3, influenza virus types A and B, and respiratory syncytial virus types A and B. One hundred forty-three respiratory specimens from 126 patients were analyzed by RT-PCR-EHA, and the results were compared to those obtained by conventional viral culture and immunofluorescence (IF) methods. RT-PCR-EHA proved to be positive for 17 of 143 (11.9%) specimens, whereas 8 of 143 (5.6%) samples were positive by viral culture and/or IF. Eight samples were positive by both RT-PCR-EHA and conventional methods, while nine samples were RT-PCR-EHA positive and viral culture and IF negative. Eight of the nine samples with discordant results were then independently tested by a different multiplex RT-PCR assay for influenza virus types A and B, and all eight proved to be positive. In comparison to viral culture and IF methods, RT-PCR-EHA gave a sensitivity and a specificity of 100 and 93%, respectively. Since RT-PCR-EHA was able to detect more positive samples, which would otherwise have been missed by routine methods, we suggest that this multiplex RT-PCR-EHA provides a highly sensitive and specific means of diagnostic detection of major respiratory viruses.

Nocardia infection in heart-lung transplant recipients at Alfred Hospital, Melbourne, Australia, 1989-1998

Nocardia infections are uncommon in recipients of heart, lung, or heart-lung transplants, but such infections are well described. Frequent episodes of rejection, high-dose prednisolone treatment, renal impairment, and prolonged respiratory support have all been shown to increase the risk of Nocardia infection in this group. In this retrospective review of 540 recipients of heart, lung, or heart-lung transplants, 10 patients developed Nocardia infection (frequency, 1.85%). Infection occurred at a mean +/- standard deviation of 13+/-14.5 months after transplantation. All patients had pulmonary disease with no evidence of extrapulmonary disease. The Nocardia infection did not contribute directly to patient deaths. Coinfection with other pathogens was present in 6 patients, and 2 patients had sequential infections. Radiological findings varied. All isolates were susceptible to trimethoprim-sulfamethoxazole, amikacin, and imipenem. Treatment regimens varied. Two (30%) of 6 patients treated with trimethoprim-sulfamethoxazole developed adverse reactions, which necessitated a change in antibiotic therapy. The optimal treatment regimen, which comprises both the antimicrobial agent and the length of treatment, is unclear.

Fusidic acid in skin and soft tissue infections

Skin and soft skin tissue infections are usually caused by Staphylococcus aureus and Streptococcus pyogenes. In vitro data show good activity of fusidic acid against staphylococci but the minimal inhibitory concentrations for streptococci are relatively high indicating marginal activity. A limited number of clinical trials have been performed using oral fusidic acid and although all have methodological problems the difference in susceptibility of these two organisms is apparent. The end of study cure rates for these studies were 91-99% for S. aureus and 75-85% for S. pyogenes. Topical therapy has been used in a number of forms and for different skin infections. Comparative studies have been conducted with mupirocin, trimethoprim/polymixin cream, hydrogen peroxide and combination steroid preparations. For most of these studies fusidic acid was equivalent to the comparator agent except where there was a proven S. pyogenes infection. Studies with topical fusidic acid have also been reported in specific disease states such as acne, erythrasma, and abscesses with good results.

Microsporidial disease in HIV-infected patients: a report of 42 patients and review of the literature

Microsporidiosis is recognized as an increasingly important infection, particularly in patients with human immunodeficiency virus (HIV) infection. In this retrospective study we have reviewed the clinical features, laboratory findings and management of 42 HIV positive patients co-infected with microsporidia. All patients had spores identified in faeces stained with a modified trichome blue stain. Patients were all markedly immunosuppressed (median CD4 20 cells/microl). Common symptoms included weight loss, diarrhoea, abdominal pain, anorexia and nausea. 29 patients were diagnosed with Enterocytozoon bieneusi infection; 13 were infected with Encephalitozoon intestinalis, and disseminated disease was confirmed in 8. Albendazole therapy in patients with E. intestinalis (but not E. bieneusi) resulted in good clinical response.

Brain abscesses caused by Burkholderia pseudomallei

Burkholderia pseudomallei is an important human pathogen in tropical areas, particularly South East Asia and Northern Australia. A fatal case of meliodosis presenting as brain abscesses is described. The patient deteriorated despite treatment and died 21 days after admission. Burkholderia pseudomallei was only isolated after administration of corticosteroids, whilst on treatment with antibiotics to which the organism later showed in vitro sensitivity. Magnetic resonance imaging was more sensitive than computed tomography in diagnosing early brainstem infection in this patient. Physicians working outside the endemic areas must be attuned to the possibility of melioidosis in any patient with an appropriate history of travel to endemic areas. The combination of striking early, extensive, confluent T2 hyperintensity with disproportionately small enhancing lesions may be characteristic of meliodosis.

Disseminated echovirus infection after allogeneic bone marrow transplantation

Disseminated enteric human cytopathogenic orphan (echo) virus infection after allogeneic bone marrow transplantation has been reported once previously: a patient developed a fatal infection with the virus being isolated from brain, lung and heart. We report a second case of disseminated echovirus infection in which virus was isolated from the stomach and liver. On this occasion the infection was associated with the development of biopsy-proven acute graft-versus-host disease of the skin, stomach, colon and liver. The infection resolved without sequelae.

High dose cytosine arabinoside is a major risk factor for the development of hepatosplenic candidiasis in patients with leukemia

A retrospective study of hepatosplenic candidiasis in patients with acute leukemia from a single centre was performed. The significance of age, sex, type of leukemia, dose of cytosine arabinoside (Ara-C), duration of neutropenia, steroid use and period of therapeutic antibiotics in the development of hepatosplenic candidiasis was analyzed, using logistic regression analysis. Nine of 51 patients had hepatosplenic candidiasis. Ara-C use was highly associated with the development of hepatosplenic candidiasis (p = 0.001); with a high association with a higher dose (p < 0.0001). On the basis of these results consideration should be given to further trial of antifungal prophylaxis for patients receiving high dose Ara-C.

Cryptosporidiosis in patients with AIDS

Cases of cryptosporidiosis in patients with the acquired immunodeficiency syndrome (AIDS) residing in Melbourne over a 6-year period (1990-1995) are described. During this period 85 cases occurred, while 979 new AIDS diagnoses were notified. Over this period temporal clustering in cryptosporidial detection was evident (P=0.007), but the pattern was not statistically associated with the season, rainfall (P=0.88), mean average maximal temperature (P=0.15) or mean average minimal temperature. Further studies should identify these risk factors and provide an opportunity to prevent this devastating disease.

Parvovirus B19 in HIV infection: a treatable cause of anemia

We describe the case of an adult male patient with AIDS who presented with severe anemia and on investigation was found to have red cell aplasia due to parvovirus B19 infection. Bone marrow examination revealed absence of erythroid development and rare giant pronormoblasts. Repeated serological examinations revealed a low level of parvovirus IgM but no IgG. Viremia was demonstrated by electron microscopy and by the polymerase chain reaction (PCR). The patient's initial hemoglobin was 45 g/l and over a four month period he required twenty units of blood. He was treated with intravenous immunoglobulin (Intragam, CSL) at a dose of 400 mg/kg/day for five days. This led to an increase in his hemoglobin to 135 g/l. Parvovirus remained detectable by PCR but not by electron microscopy. Six months later the patient relapsed (Hb 65 g/l). Again he was transfused and treated with intravenous immunoglobulin for five days. His hemoglobin rose to 153 g/l and remained stable. He subsequently received maintenance treatment with 30 g of intagram once a month. We recommend that parvovirus be considered in any HIV infected patient with recurrent anemia.

Helicobacter cinaedi bacteraemia: varied clinical manifestations in three homosexual males

We report 3 cases of Helicobacter cinaedi bacteraemia in different hosts representing a spectrum of clinical illness associated with this infection. The first was an AIDS patient with relapsing H. cinaedi bacteraemia despite antibiotic treatment. The second was an HIV seronegative homosexual man with end-stage renal failure, receiving haemodialysis and a previous history of chronic lymphoedema of his legs. He developed H. cinaedi bacteraemia with cellulitis of his left leg. Patient 3, an HIV seronegative homosexual man, had transient H. cinaedi bacteraemia 2 days after the completion of a course of chemotherapy for bilateral testicular carcinoma. The clinical spectrum of disease associated with H. cinaedi is broad, with few specific clinical features. Successful recovery of this fastidious organism from blood aids in the diagnosis of this unusual infection.

The usage and costs of health services for HIV infection in Australia

OBJECTIVE

To describe patterns of health-service usage and the resulting costs in 1992-1993 for Australian men.

DESIGN

A prospective survey, stratified by phase of illness.

SETTING

Hospital and community-based care.

PATIENTS

A total of 128 homosexual men: 20 in phase 1 (CD4+ count > or = 500 x 10(6)/l), 31 in phase 2 (CD4+ count < 500 and > or = 200 x 10(6)/l), 30 in phase 3 (CD4+ count < 200 x 10(6)/l), and 47 in phase 4 (AIDS).

MAIN OUTCOME MEASURES

Mean monthly service usage rates and costs.

RESULTS

Health-service utilization increased and became more hospital-based as illness worsened; the main exception was use of antiretroviral drugs, which peaked in phases 2 and 3. Hospital admission was rare before diagnosis of AIDS. Hospital bed-days per patient per month averaged 3.3 for AIDS patients until the final 3 months of life increasing to 15.8 in the 3 months before death. Mean monthly costs (in 1992-1993 Australian dollars) were $331 [95% confidence interval (CI), 218-455] in phase 1, $667 (95% CI, 540-836) in phase 2, $1372 (95% CI, 1044-1776) in phase 3, and $4615 (95% CI, 3456-5985) for AIDS patients until the last 3 months of life and $13,308 (95% CI, 10,538-16,516) in the 3 months before death. Drugs comprised 57% of total costs in phase 1, but only 30% of costs for patients with AIDS, whereas hospital bed-days comprised 10% of phase 1 costs and 60% of AIDS costs.

CONCLUSIONS

Health-care utilization and resulting costs increased with severity of illness, and were particularly high for AIDS patients in the 3 months before death. Service-utilization patterns and components of costs varied between each phase.

CD4 lymphocyte numbers after splenectomy in patients infected with the human immunodeficiency virus

Splenectomy has been reported to alter inconsistently the CD4 lymphocyte numbers in patients infected with the human immunodeficiency virus (HIV). To further assess the effect of splenectomy we have retrospectively examined the charts of 10 patients who were infected with HIV and who had undergone splenectomy. There was a significant increase in the mean CD4 numbers following splenectomy (mean increase of 326/microliters, or 2.1-fold, P = 0.0009), the total lymphocyte numbers (mean increase of 1.55/ml, or 2.2-fold, P = 0.001) and in the CD8 lymphocyte count (mean increase of 968/microliters, or 2.3-fold, P = 0.014). No significant difference was observed in the percentage CD4 lymphocytes (P = 0.95) or in the CD4:CD8 lymphocyte ratio (P = 0.76). In two patients, symptoms suggestive of impaired immune function developed post-splenectomy, at a time when their CD4 lymphocyte numbers were markedly higher than their pre-splenectomy values. One developed oral candidiasis (CD4 960/microliters, percentage CD4 32%), and in one patient a 7 kg weight loss was associated with recurrent mouth ulcers (CD4 680/microliters, percentage CD4 7%). We conclude that the total CD4 count increases significantly after splenectomy while the percentage CD4 lymphocyte count and CD4:CD8 lymphocyte ratio do not. Our data suggest that the CD4 lymphocyte count overestimates the immune function in these patients, although our findings are not conclusive.

Phenotypic variation of Staphylococcus epidermidis isolated from a patient with native valve endocarditis

Two colonial variants of Staphylococcus epidermidis were isolated from the valvular tissue of a patient with native valve endocarditis. In addition to differing in colonial morphology, the two variants differed in hemolysis on blood-containing media, in adherence capacity, and in the expression of certain enzymes. Under suitable conditions, both variants were themselves capable of phenotypic variation, although they differed in the rate at which variants were generated. The variants yielded identical profiles on restriction endonuclease analysis of plasmid DNA and pulsed-field gel electrophoresis of whole-cell DNA. This report suggests a possible role for phenotypic variation in coagulase-negative staphylococcal virulence. Congo red agar would be an excellent medium for studying the contribution of variation to the virulence of these organisms.

Animal bites and infections

Animal bites are not a common reason for attendance at a large public hospital casualty department. Victims of bites may more commonly present in general practice. This review of animal bites is adapted from an article in the Alfred Hospital Infectious Diseases Newsletter, which is edited by Dr Denis Spelman, Physician in Bacteriology.

Human immunodeficiency virus testing

This article outlines an approach to counselling a patient before a HIV test. Preparing such a patient for the possibility of a positive test, and all it means, is essential. It is also important to discuss with a seronegative patient measures to avoid infection. This feature, which presents the latest information on infectious diseases, is an adaptation of material presented in the Alfred Hospital Infectious Diseases Newsletter, edited by Dr Denis Spelman, Physician in Bacteriology.