Performance of an automated chemiluminescence SARS-CoV-2 IG-G assay.

INTRODUCTION: We describe our evaluation of the Abbott SARS-CoV-2 IgG assay on the Architect immunoassay analyser. METHODS: We assessed assay precision, sensitivity, specificity, positive/negative predictive values (PPV/NPV), cross-reactivity (influenza/dengue/hepatitis B and C/rheumatoid factor/anti-nuclear/double-stranded DNA/syphilis) and sample throughput in samples from real-time polymerase chain reaction (RT-PCR) positive patients/healthcare workers (HCWs)/pre-pandemic samples. We compared the cut-off indexes (COIs) between all control samples (HCWs and pre-pandemic) to generate an optimised COI limit for reactivity. RESULTS: The assay specificity was 99.8% (n = 980) and sensitivity was 45.9-96.7% (n = 279). When tested ≥ 14 days post-positive RT-PCR (POS), the PPV/NPV was 96.4%/99.8%. The difference between the COIs of HCWs/pre-pandemic samples was small (0.01, p < 0.0001). There was minimal cross-reactivity with other antibodies. A lower COI limit for reactivity (≥0.55, using the 99th percentile COI of our controls and ROC analysis) improved diagnostic sensitivity, especially at 0-6 days POS (45.9-55.8%), with a small decrease in specificity (98.9%). The assay throughput was 100 samples in 70 min. CONCLUSION: The Abbott SARS-CoV-2 IgG assay shows excellent performance in patients ≥ 14 days POS. The difference between the COIs of HCWs and pre-pandemic samples was numerically small. A lower COI limit improves assay sensitivity with a slight decrease in specificity.

Localised outbreak of Falciparum malaria in Singapore.

Malaria is primarily an imported disease in Singapore. Local outbreaks are uncommon. We describe a localised outbreak of three patients with Falciparum malaria, which we believe to be locally acquired. There was one fatality due to severe disease and late presentation. Malaria should be considered as a cause of febrile illness as the likelihood of cure depends on early detection and treatment.

Extended-spectrum beta-lactamases in clinical isolates of Escherichia coli and Klebsiella spp. in a Singapore hospital: clinical spectrum.

INTRODUCTION: The rising prevalence of extended-spectrum beta-lactamases in gram-negative bacillary pathogens is an important clinical problem resulting from the extensive use of broad-spectrum antibiotics. The emergence of the extended-spectrum beta-lactamases increases the possibility that traditional, empiric antimicrobial regimens may be ineffective. The aims of this study are: to determine the epidemiologic characteristics and clinical outcome of patients diagnosed with infection caused by Klebsiella spp. and Escherichia coli producing extended-spectrum beta-lactamases; to define a subgroup of patients who may benefit from early, empiric therapy; and to determine the local antibiotic sensitivity pattern in order to improve antibiotic utilisation in our hospital. MATERIALS AND METHODS: A 4-month retrospective review of patients hospitalised in Changi General Hospital between November 2000 and February 2001 who were diagnosed with infection caused by isolates of Klebsiella spp. or Escherichia coli producing extended-spectrum beta-lactamases. RESULTS: During the study period, 44 % of Klebsiella spp. and 16.1 % of Escherichia coli isolates were reported as producers of the extended-spectrum beta-lactamases. Sixty-eight patients were assessed to have clinically significant infection caused by 75 isolates. Most of them were elderly, had multiple medical problems and were recently treated with beta-lactam antibiotics. There was a trend toward better outcome in patients who received adequate initial, empiric therapy. CONCLUSION: Patients with infections caused by extended-spectrum beta-lactamase producing Enterobacteriaceae have certain identifiable, common clinical characteristics. In our institution, only carbapenems remain effective against all isolates of Klebsiella spp. or Escherichia coli producing extended-spectrum beta-lactamases. Further research is necessary to define a group of patients who can benefit from an early, broad-spectrum, empiric therapy.

Dapsone hypersensitivity syndrome masquerading as a viral exanthem: three cases and a mini-review.

INTRODUCTION: We report 3 cases of dapsone hypersensitivity syndrome due to anti-malarial chemoprophylactic treatment with maloprim, in military servicemen, presenting like a viral exanthem. CLINICAL PICTURE: Three male military recruits presented with fever and rash, 6 to 8 weeks after commencing on weekly doses of maloprim. TREATMENT: A course of topical and systemic corticosteroids and oral antihistamines were started. OUTCOME: All cases showed gradual resolution of fever, rash and eventual normalisation of liver function test. CONCLUSION: A high index of suspicion was required before this uncommon syndrome can be recognised. Early institution of corticosteroid therapy and discontinuation of maloprim are the mainstays of treatment.

A case of right loin pain: septic ovarian vein thrombosis due to Campylobacter fetus bacteraemia.

INTRODUCTION: Septic ovarian venous thrombosis is an uncommon condition. Diagnosis is often not immediately apparent clinically and there are many that mimic this condition. We described an unusual case of septic ovarian vein thrombosis associated with Campylobacter fetus (C. fetus) bacteraemia. CLINICAL PICTURE: A 46-year-old female presented with fever and acute right loin pain. Right ovarian venous thrombosis was demonstrated on sonography and confirmed with computed tomography and magnetic resonance imaging. C. fetus was isolated from the blood. TREATMENT AND OUTCOME: The patient was given antibiotics and anticoagulation therapy with good response. CONCLUSION: Septic ovarian vein thrombosis should be considered as a differential diagnosis in female patients presenting with fever associated with lower abdominal pain. C. fetus bacteraemia also predisposes to thrombophlebitis, including septic ovarian vein thrombosis. When they are diagnosed in a timely manner and treated appropriately, the response is good and potential serious complications, including thromboembolism, and death could be averted. Radiological imaging is useful in the diagnostic work-up of this condition.

Influenza A H1N1 (2009): clinical spectrum of disease among adult patients admitted to a regional hospital in Singapore.

INTRODUCTION: The worldwide spread of Influenza A H1N1 (2009) has proceeded at an unprecedented rate, with the World Health Organization rapidly raising its influenza pandemic alert to phase six. We describe the disease spectrum of H1N1 (2009) to aid the triaging and identification of patients at risk. METHODS: This is a retrospective chart review of all confirmed H1N1 (2009) cases admitted to our institution between June and September 2009. RESULTS: The disease severity of the 153 patients studied was classified as mild (n is 75), moderate (n is 55) and severe (n is 23). 81 patients were female. The median age was 26 years. While comorbidities were more prevalent among patients with moderate-severe illness, 47.4 percent reported no pre-existing illness. Presenting complaints of breathlessness, tachycardia, low-pulse oximetry, higher leukocyte counts and C-reactive protein with low albumin levels were more commonly noted in moderate-severe illness (p-value less than 0.001). All patients received oseltamivir at a median of four days from illness onset. 18 required intensive care unit admission, with the majority (94.4 percent) within the first 24 hours of hospitalisation. The overall mortality rate was 4.6 percent. Median lengths of hospitalisation were four and nine days for moderate and severe cases, respectively. CONCLUSION: While the majority of H1N1 (2009) patients have mild illness, a subgroup can become critically ill. Prior good health is not necessarily a good discriminator against severe illness. The presence of dyspnoea, tachycardia and desaturation at triage should heighten the index of suspicion for H1N1 (2009)-related complications.

Epidemiology and clinical outcome of enterococcal bacteraemia in an acute care hospital.

OBJECTIVE: To determine the epidemiology and clinical outcome of enterococcal bacteraemia in an acute care hospital. MATERIALS AND METHODS: This is a retrospective study on enterococcal bacteraemia in an acute hospital from January 1999 to June 2001. Patients' clinical case notes were reviewed and their demographic, clinical and microbiological data were recorded. RESULTS: A total of 42 patients (25 males and 17 females) were included in the study, their mean age was 74.8+/-10.9 years. The majority of them had underlying diabetes mellitus and neurological disease. Seventeen patients required intensive care. Sources of enterococcal bacteraemia were identified in 21 cases (urinary tract, 13 patients; hepatobiliary, five; cardiovascular, two and soft tissues, one patient). Eighteen patients had prior invasive procedures. All the Enterococcus species isolated were vancomycin-susceptible; however, eight were ampicillin-resistant and 13 had high-level gentamicin resistance. Shock, disseminated intravascular coagulopathy, acute renal failure and cardiorespiratory arrest occurred in 42% of the cases. Antibiotics were prescribed appropriately in 31 patients and seven deaths were recorded. Of the 11 patients who received inappropriate therapy, six deaths were recorded. Inappropriate antibiotic therapy was associated with mortality. The mortality rate was 31%. Only one patient had a relapse of enterococcal bacteraemia from urinary tract infection secondary to underlying ureteric stricture. There were no vancomycin resistant cases. CONCLUSION: Urinary tract infection was the most common source of enterococcal bacteraemia. Appropriate antibiotics were essential in treating bacteraemia to reduce mortality. Vancomycin-resistant Enterococcus was not detected. The presence of comorbid conditions and invasive procedures in patients with enterococcal bacteraemia were found in 86 and 71% of patients, respectively.