VRE acquisition in hospital and its association with hospital antimicrobial usage -a non-linear analysis of an extended time series

BACKGROUND

Vancomycin resistant enterococci (VRE) have become endemic pathogens in many Australian hospitals causing significant morbidity. There are few observational studies that have evaluated the effect of antibiotic usage on VRE acquisition. This study examined VRE acquisition and its association with antimicrobial use. The setting was a NSW tertiary hospital with 800 beds over a 63 month period up to March 2020, straddling piperacillin-tazobactam (PT) shortages that occurred from in September 2017.

METHODS

The primary outcome was monthly inpatient hospital onset Vancomycin-resistant Enterococci (VRE) acquisitions. Multivariate adaptive regression splines (MARS) were used to estimate hypothetical thresholds, where antimicrobial use above threshold is associated with increased incidence of hospital onset VRE acquisition. Specific antimicrobials and categorised usage (broad, less broad and narrow spectrum) were modelled.

RESULTS

There were 846 hospital onset VRE detections over the study period. Hospital onset vanB and vanA VRE acquisitions fell significantly by 64% and 36% respectively after the PT shortage. MARS modelling indicated that PT usage was the only antibiotic found to exhibit a meaningful threshold. PT usage greater than 17.4 defined daily doses/1000 occupied bed-days (95%C I: 13.4, 20.5) was associated with higher onset of hospital VRE.

CONCLUSIONS

This paper highlights the large, sustained impact that reduced broad spectrum antimicrobial use had on VRE acquisition and showed that PT use in particular was a major driver with a relatively low threshold. It raises the question as to whether hospitals should be determining local antimicrobial usage targets based on direct evidence from local data analysed with non-linear methods.

Cefazolin susceptibility of coagulase-negative staphylococci (CoNS) causing late-onset neonatal bacteraemia

BACKGROUND

CoNS bacteraemia causes significant neonatal morbidity. Previous work has suggested that β-lactam antibiotics vary in their binding affinity to PBP2a (produced by the mecA gene) present in most CoNS.

OBJECTIVES

We evaluated cefazolin MICs for CoNS isolated in an Australian neonatal ICU (NICU) and correlated them with isolate genotype and phenotype.

METHODS

Significant blood isolates from 2009 to 2017 were speciated and underwent broth microdilution testing for cefazolin, cefoxitin, oxacillin and flucloxacillin. Correlation with mecA presence and PBP2a expression was evaluated. A selection of Staphylococcus capitis isolates underwent WGS.

RESULTS

The CoNS (n = 99) isolates were confirmed as S. capitis (n = 57), Staphylococcus epidermidis (n = 32), Staphylococcus haemolyticus (n = 2) and Staphylococcus warneri (n = 8). The MIC of cefazolin was ≤2 mg/L for 30% of isolates and 75% had an MIC of ≤8 mg/L (MIC90 = 16 mg/L). This contrasted with MIC90s of cefoxitin, oxacillin and flucloxacillin, which were all ≥32 mg/L. WGS found a number of S. capitis isolates closely related to the globally established NRCS-A clone.

CONCLUSIONS

CoNS displayed distinctly lower MIC values of cefazolin than of other agents tested. MIC variation may be related to binding affinity of PBP2a or regulation of expression of mecA by mecR1-mecI functional genes. Further, NRCS-A S. capitis strains were present in this Australian NICU before and after the unit underwent physical relocation, which raised questions about a common environmental source. It is considered justified to conduct a randomized clinical trial that assesses cefazolin versus vancomycin for management of late-onset neonatal sepsis.

The influence of cultural food security on cultural identity and well-being: a qualitative comparison between second-generation American and international students in the United States

The purpose of this study was to explore the impact of cultural food insecurity on identity and well-being in second-generation American and international university students. Thirty-one semi-structured interviews were conducted from January-April 2020. Audio transcripts were analyzed using continuous and abductive thematic analysis. Students indicated that cultural foodways enhanced their well-being by facilitating their cultural/ethnic identity maintenance, connection, and expression. Conversely, cultural food insecurity diminished student well-being due to reduced cultural anchors, highlighting the importance of cultural food in this population. Universities that reduce cultural foodways barriers may mitigate cultural food insecurity for second-generation American and international university students. (100/100).

How accurately is hospital acquired pneumonia documented for the correct assignment of a hospital acquired complication (HAC)?

BACKGROUND

In 2016, the Australian Commission on Safety and Quality in Healthcare (ACSQHC) released a list of 16 categories of potentially preventable, high impact hospital-acquired complications (HAC) identified by using administrative coded data (ACD). An important category are hospital-acquired infections (HAI). Within this category, hospital-acquired pneumonia (HAP) is among the most frequent complications documented. There are no published studies concerning the current ACSQHC approach to HAI surveillance using ACD and no pneumonia-specific ACD studies reported from Australia. Published work indicates that ACD detection of HAP has low a sensitivity and positive predictive value (PPV). The current study was designed to examine whether coders correctly reflected the documentation of HAP that was present in the medical record and also evaluated the medical documentation that was present.

METHODS

One hundred patients with ACD encoded HAP were selected for review, drawn from admissions to 2 Hunter New England Health hospitals during 2017. Patient records and the eMR were reviewed by two medical officers to assess medical and radiological documentation of pneumonia. The district coding manager reviewed the accuracy of coding of a subset of 23 cases where medical review had not located documented evidence of HAP.

RESULTS

Of the 100 reviewed cases, the median patient age was 75 years (range 0-95 years) with 3% under 16 years of age. Twenty one were intensive care-associated of which 13 were associated with ventilation. In 23 cases the documentation was disputed and a secondary review took place - the coding manager confirmed coding changes in 14 of these 23 cases.

CONCLUSIONS

This study found that administrative coded data of HAP, utilizing the ACSQHC method reliably reflected the available documentation with a PPV of 86% (95% binomial exact confidence interval 77-92%), much higher than documented by previous ACD studies. The actual documentation of pneumonia by medical staff frequently used the non-specific term 'lower respiratory infection (LRTI)' which we recommend to be avoided. Radiological confirmation was absent in one third of cases. We recommend the adoption of a medical note template checklist for HAP to prompt clinicians with the accepted diagnostic criteria. We also recommend documenting a reason as to why any antibiotic has been commenced in a hospitalized patient in accord with the ACSQHC Antimicrobial Stewardship Clinical Care Standard.

A predictive model of days from infection to discharge in patients with healthcare-associated urinary tract infections: a structural equation modelling approach

BACKGROUND

Length of stay (LOS) in hospital is an important component of describing how costs change in relation to healthcare-associated infection and this variable underpins models used to evaluate cost. It this therefore imperative that estimations of LOS associated with infections are performed accurately.

AIM

To test the relationships between the size of hospital, age, and patient comorbidity on days from admission to infection and days from infection to discharge in patients with a healthcare-associated urinary tract infection (HAUTI), using structural equation modelling (SEM).

METHODS

A non-current cohort study in eight hospitals in New South Wales, Australia. All patients admitted to the hospital for >48 h and who acquired a HAUTI were included.

FINDINGS

From the 162,503 eligible patient admissions, 2821 (1.73%) acquired a HAUTI. SEM showed that the proposed model had acceptable fit indices for the combined sample (GFI = 1.00; AGFI = 1.00; NFI = 1.00; CFI = 1.00; RMSEA = 0.000). The main findings showed that age of patient had a direct association with days from admission to infection and with days from infection to discharge. Patient comorbidity had direct links to the variables days from admission to infection and days from infection to discharge. Multi-group analysis indicated that the age of male patients was more influential on the factor days from admission to infection when compared to female patients. Furthermore, the number of comorbidities was significantly more influential on days from admission to infection in male patients than in female patients.

CONCLUSION

As the first published study to use SEM to explore a healthcare-associated infection and the predictors of days from infection to discharge in hospital, we can confirm that accounting for the timing of infection during hospitalization is important and that patient comorbidity influences the timing of infection.

Australasian Society of Infectious Diseases updated guidelines for the management of Clostridium difficile infection in adults and children in Australia and New Zealand

The incidence of Clostridium difficile infection (CDI) continues to rise, whilst treatment remains problematic due to recurrent, refractory and potentially severe nature of disease. The treatment of C. difficile is a challenge for community and hospital-based clinicians. With the advent of an expanding therapeutic arsenal against C. difficile since the last published Australasian guidelines, an update on CDI treatment recommendations for Australasian clinicians was required. On behalf of the Australasian Society of Infectious Diseases, we present the updated guidelines for the management of CDI in adults and children.

Antibiotic therapy for inducible AmpC β-lactamase-producing Gram-negative bacilli: what are the alternatives to carbapenems, quinolones and aminoglycosides?

Some bacteria that possess chromosomally determined AmpC β-lactamases may express these enzymes at a high level following exposure to β-lactams, either by induction or selection for derepressed mutants. This may lead to clinical failure even if an isolate initially tests susceptible in vitro, a phenomenon best characterised by third-generation cephalosporin therapy for Enterobacter bacteraemia or meningitis. Several other Enterobacteriaceae, such as Serratia marcescens, Citrobacter freundii, Providencia spp. and Morganella morganii (often termed the 'ESCPM' group), may also express high levels of AmpC. However, the risk of clinical failure with β-lactams that test susceptible in vitro is less clear in these species than for Enterobacter. Laboratories frequently do not report β-lactam or β-lactamase inhibitor combination drug susceptibilities for ESCPM organisms, encouraging alternative therapy with quinolones, aminoglycosides or carbapenems. However, quinolones and carbapenems present problems with selective pressure for multiresistant organisms, and aminoglycosides with potential toxicity. The risk of emergent AmpC-mediated resistance for non-Enterobacter spp. appears rare in clinical studies. Piperacillin/tazobactam may remain effective and may be less selective for AmpC derepressed mutants than cephalosporins. The potential roles for agents such as cefepime or trimethoprim/sulfamethoxazole are also discussed. Clinical studies that better define optimal treatment for this group of bacteria are required.

Preventing healthcare-associated infection: risks, healthcare systems and behaviour

More than 177 000 potentially preventable healthcare‐associated infections (HAIs) occur per annum in Australia with sizable attributable mortality. Organizational systems to protect against HAI in hospitals in Australia are relatively poorly developed. Awareness and practice of infection control by medical and other healthcare staff are often poor. These lapses in practice create significant risk for patients and staff from HAI. Excessive patient exposure to antimicrobials is another key factor in the emergence of antibiotic‐resistant bacteria and Clostridium difficile infection. Physicians must ensure that their interactions with patients are safe from the infection prevention standpoint. The critical preventative practice is hand hygiene in accord with the World Health Organization 5 moments model. Improving the use of antimicrobials, asepsis and immunization also has great importance. Hospitals should measure and feed back HAI rates to clinical teams. Physicians as leaders, role models and educators play an important part in promoting adherence to safe practices by other staff and students. They are also potentially effective system engineers who can embed safer practices in all elements of patient care and promote essential structural and organizational change. Patients and the public in general are becoming increasingly aware of the risk of infection when entering a hospital and expect their carers to adhere to safe practice. Poor infection control practice will be regarded in a negative light by patients and their families, regardless of any other manifest skills of the practitioner.

Pulsed-field gel electrophoresis is a useful tool in the monitoring of methicillin-resistant Staphylococcus aureus epidemic outbreaks in the intensive care unit

We wished to determine how pulsed-field gel electrophoresis may be of use in monitoring methicillin-resistant Staphylococcus aureus (MRSA) outbreaks in the intensive care unit (ICU). A retrospective epidemiological analysis was conducted. All 27 ICU patients and 11 patients from other hospital wards from whom MRSA was isolated over a one year period were included in the study. Seventeen of the 27 ICU MRSA isolates were analysed by pulsed-field gel electrophoresis for clonality and compared with the 11 other hospital isolates genotypes over the same period. During three MRSA outbreaks, five MRSA genotypes were identified in ICU whilst the same five genotypes and three additional were found in the rest of the hospital. Pulsed-field gel electrophoresis analysis was useful in identifying clonality of ICU MRSA infections and establishing that they were imported from hospital wards, rather than arising de novo in ICU. We were further able to identify clonal clusters within the unit linked by temporal and geographical proximity, suggestive of cross-infection. Pulsed-field gel electrophoresis typing might be additionally useful in tracing the source of human and/or environmental factors if a genotype were persistently identified.

A population-based study of children with cerebral tuberculosis in New South Wales

OBJECTIVE

To determine the incidence of childhood cerebral tuberculosis (tuberculous meningitis [TBM] and tuberculoma) in a defined population.

DESIGN

Retrospective, population-based study.

SETTING AND PARTICIPANTS

All resident children aged up to 14 years in New South Wales diagnosed with cerebral tuberculosis, from 1982 to 1996.

MAIN OUTCOME MEASURE

Population-based incidence of childhood TBM.

RESULTS

10 children with TBM and one with tuberculoma were identified in the 15 years. The incidence of TBM was 0.053 (95% CI, 0.025-0.097) per 100,000. Eight of the 10 TBM patients were born in Australia and five were of white European origin. Only one had been vaccinated with BCG vaccine. Three of the children died.

CONCLUSIONS

The incidence of childhood TBM in New South Wales is low, and comparable with that in other First World countries.

Should third-generation cephalosporins be the empirical treatment of choice for severe community-acquired pneumonia in adults?

The choice of empirical treatment for community-acquired pneumonia (CAP) is highly controversial. Our survey of 42 Australian emergency department doctors showed that monotherapy with a third-generation cephalosporin was the preferred regimen for severe CAP (14/42; 33%). We argue that cheaper regimens with a narrower spectrum are likely to be just as effective as third-generation cephalosporins and will have fewer adverse effects on the microbial ecology of hospitals. We suggest penicillin or ampicillin (to cover pneumococci--even if penicillin "resistant"--and Haemophilus influenzae), plus a macrolide (e.g., azithromycin or erythromycin; to cover Legionella and other "atypical" pathogens), plus a single large dose of an aminoglycoside (e.g., gentamicin; to cover gram-negative bacilli such as Klebsiella pneumoniae) as empirical therapy for severe CAP.

Progressive vaccinia treated with ribavirin and vaccinia immune globulin

A 67-year-old man with metastatic melanoma and chronic lymphocytic leukemia was inadvertently given a vaccinia melanoma oncolysate vaccination. He developed progressive vaccinia at the site of inoculation. The lesion started to heal only when he was treated with ribavirin. Vaccinia immune globulin was administered and appeared to help control the initial lesion and limit the development of satellite lesions.

Primary cryptococcal cellulitis caused by Cryptococcus neoformans var. gattii in an immunocompetent host

Primary cutaneous cryptococcal infection is uncommon. The cutaneous manifestations are most often the result of dissemination from the central nervous system or lung, usually in an immunocompromised host; cellulitis is regarded as the rarest cutaneous form. Primary cutaneous cryptococcosis has occasionally been reported in the immunocompetent, the causative organism being Cryptococcus neoformans var. neoformans. We present a case of cellulitis of the right arm in a 75-year-old man caused by Cryptococcus neoformans var. gattii, a fungus which is endemic in Australia and an important cause of infection in the immunocompetent. This is the first case described of a primary cutaneous infection due to Cryptococcus neoformans var. gattii. The interesting ecology of this organism is discussed.

Risk-stratified nosocomial infection surveillance in a neonatal intensive care unit: report on 24 months of surveillance

OBJECTIVE

To document the nosocomial infection rate in a single neonatal intensive care unit (NICU) in terms of patient workload and device utilization.

METHODOLOGY

Nosocomial infections have been identified and documented by the methodology described by the National Nosocomial Infection Surveillance System (NNIS), Centres for Disease Control, Atlanta. In addition, antibiotic usage has been surveyed in the NICU and standardized measures of patient exposure to antibiotics stratified by birthweight and gestational age have been described.

RESULTS

Overall nosocomial infection rates compared favourably with the published NNIS figures at 6.2 infections per 100 admissions or 4.8 per 1000 patient days. Infection rates were significantly higher in lower birthweight groups. Device-related infection rates in each birthweight cohort were also very close to published figures and varied less with birthweight group. Antibiotic exposure averaged 12% of total admission days, less than previously published data.

CONCLUSIONS

The NNIS system is applicable to Australian NICU and provides an effective tool for monitoring infection episodes.

Prospective study of diarrhoeal outbreaks in child long-daycare centres in western Sydney

OBJECTIVE

To investigate outbreaks of diarrhoeal illness in children attending long-daycare centres (LDCs), to characterise parasitic, bacterial and viral isolates from the children's faeces and to identify individual and LDC risk factors for diarrhoea.

DESIGN

Eleven-month prospective case-control study of diarrhoeal outbreaks among children in LDCs.

SUBJECTS

2368 children attending 35 LDCs in the western Sydney area.

MAIN OUTCOME MEASURES

Frequency of diarrhoeal outbreaks, rate of attack and spread to family members; pathogens isolated from stools; and individual and LDC risk factors.

RESULTS

The overall incidence of diarrhoeal disease was low (0.28 outbreaks per centre per year and 0.056 outbreak-associated cases per child-year). Attack rates during outbreaks varied widely (4%-55%; mean, 15%), as did secondary spread rates to family members (1%-15%; mean, 9%). Pathogens were isolated from 7% of symptomatic children and 7% of controls; no outbreak was shown to be caused by a recognised pathogen. Children with outbreak-associated diarrhoeal illness were more likely to have suffered vomiting, poor appetite, lack of energy, fever and to have taken antibiotics in the previous week than other children. Hygiene practices varied widely among centres.

CONCLUSIONS

We found low incidence and morbidity from diarrhoeal illness in Australian urban LDCs. Diarrhoea in children in LDCs may be caused predominantly by non-infectious factors such as diet and antibiotic exposure. Current hygiene measures in LDCs seem adequate to prevent and contain outbreaks of infectious diarrhoea.

Prostate-specific antigen detected prostate cancer: pathological characteristics of ultrasound visible versus ultrasound invisible tumors

Most studies examining the issue of 'early detection of prostate cancer' advocate the combined use of serum prostate-specific antigen (PSA) and digital rectal examination (DRE). As a result, a significant number of new prostate cancers are diagnosed on the basis of an elevated serum PSA when the DRE is unremarkable. The purpose of this study is to determine if the PSA-detected tumors that are visible on transrectal ultrasound (TRUS) have the same pathological characteristics as PSA-detected tumors that are invisible on TRUS. One hundred and ninety-four patients with an elevated serum PSA concentration and nonpalpable prostate cancer who underwent radical retropubic prostatectomy (RRP) at our institution between March 1988 and December 1991 were reviewed. The patients were divided into two groups: 97 (50%) had no identifiable lesion on TRUS, and 97 (50%) had at least one hypoechoic area consistent with adenocarcinoma of the prostate. The pathological characteristics of the RRP specimens from the two groups were compared. There was no significant difference in the age (p = 0.14) or the preoperative serum PSA values (p = 0.18) between the groups. Also, there was no significant difference between the groups with regard to tumor volume (p = 0.89), focality of the cancer (p = 0.43), Gleason score (p = 0.81), DNA ploidy status (p = 0.96), pathological stage (p = 0.92), surgical margin involvement (p = 0.27), and tumor location (p = 0.64). These findings suggest that the clinical TNM staging system for prostate cancer may be simplified by eliminating the distinction between PSA-detected cancers visible on TRUS and PSA detected cancers not visible on TRUS.(ABSTRACT TRUNCATED AT 250 WORDS)

Patient evaluation if prostate-specific antigen becomes elevated following radical prostatectomy or radiation therapy

Prostate-specific antigen (PSA) is the most sensitive and clinically useful method for monitoring patients following definitive therapy for prostate cancer. A "detectable" value following radical prostatectomy and an increasing level following radiation therapy are both indicative of recurrent/residual disease. The persistent cancer may be local or distant; the rate of increase of serum PSA can be useful in distinguishing between local and metastatic disease. A computed tomography or magnetic residence imaging scan may be useful for evaluating abdominal and pelvic lymph nodes, and the radionuclide bone scan is an effective tool for assessing the skeleton when the serum PSA concentration becomes elevated following treatment.

Skin thickness in patients with acromegaly and Cushing's syndrome and response to treatment

Radiological assessment of skin thickness (ST) was assessed in 22 patients with acromegaly and 17 patients with Cushing's syndrome. The age ranges of the patients studied and the 55 individuals in the control group were comparable. The skin thickness in males was significantly greater than in females (P less than 0.01). Mean skin thickness in patients with acromegaly and Cushing's syndrome was significantly greater and less respectively than the mean skin thickness of the normal controls (P less than 0.02). Following successful treatment of acromegaly (growth hormone less than 5 micrograms/l) there was a significant reduction in skin thickness (P less than 0.02 males: P less than 0.01 females). The skin thickness declined at approximately 0.3 mm/year for the first two years and more slowly thereafter. A highly significant correlation was observed between the logarithm of the pre and post treatment plasma GH concentrations and ST values. With one exception, all patients with growth hormone (GH) levels greater than 5 micrograms/l had ST values above the normal range. At an average of 4.5 years after successful treatment of Cushing's syndrome the average increase in ST was 0.23 mm (P less than 0.01). It is concluded that the measurement of skin thickness is a useful screening test for both acromegaly and Cushing's syndrome and provides an objective assessment of the clinical response to treatment.

Prevalence of fungi during Skylab missions

Samples for mycological analysis were collected from surfaces in the Skylab spacecraft before launch and during flight for each manned mission. Fungal contamination levels were low during the first two flights; however, the species recovered were different for each mission. On the third mission, widespread contamination of the Skylab spacecraft with Aspergillus and Pencillium spp. was detected. This contamination was traced to several contaminated space suit undergarments.

Slide staining device for use during space flight

A slide staining device is described that performs Gram and Wright stains during space flight. Reagents and liquid wastes are contained within a closed system.

Microbiological sampling of the spacecraft atmosphere during a simulated skylab mission

A skylab Air Sampler (SAS) has been developed for the use during Skylab missions. The SAS was used in the Skylab Medical Experiments Altitude Test (SMEAT) to gather baseline data which could be directly compared to data obtained during actual Skylab missions. The results obtained in the SMEAT gave no evidence of consistent change in either concentration or types of microorganisms in the SMEAT atmosphere over the 56-d test. Microorganisms found included some potential pathogens but were largely normal human microflora. Few typical soil microorganisms were found. These findings are related to commonly anticipated effects of long-term spaceflights on environmental microflora and to other closed environment studies.

Methods used to monitor the microbial load of returned lunar material

Methods employed to prepare lunar soil samples and procedures used to detect viable microorganisms are described.

Interaction between Escherichia coli and Pseudomonas aeruginosa in mixed cultures

Both continuous and stationary cultures were used to detect interactions between Escherichia coli and Pseudomonas aeruginosa in mixed cultures, with pure cultures included as controls. The interactions observed were both pH and substrate dependent. Stimulation of P. aeruginosa in mixture was the most marked interaction, and was, in part, due to changes in carbohydrate metabolism.