Evaluation of the INDICAID COVID-19 Rapid Antigen Test in Symptomatic Populations and Asymptomatic Community Testing.

As the COVID-19 pandemic progresses, there is an increasing need for rapid, accessible assays for SARS-CoV-2 detection. We present a clinical evaluation and real-world implementation of the INDICAID COVID-19 rapid antigen test (INDICAID rapid test). A multisite clinical evaluation of the INDICAID rapid test using prospectively collected nasal (bilateral anterior) swab samples from symptomatic subjects was performed. The INDICAID rapid test demonstrated a positive percent agreement (PPA) and negative percent agreement (NPA) of 85.3% (95% confidence interval [95% CI], 75.6% to 91.6%) and 94.9% (95% CI, 91.6% to 96.9%), respectively, compared to laboratory-based reverse transcriptase PCR (RT-PCR) using nasal specimens. The INDICAID rapid test was then implemented at COVID-19 outbreak screening centers in Hong Kong as part of a testing algorithm (termed "dual-track") to screen asymptomatic individuals for prioritization for confirmatory RT-PCR testing. In one approach, preliminary positive INDICAID rapid test results triggered expedited processing for laboratory-based RT-PCR, reducing the average time to confirmatory result from 10.85 h to 7.0 h. In a second approach, preliminary positive results triggered subsequent testing with an onsite rapid RT-PCR, reducing the average time to confirmatory result to 0.84 h. In 22,994 asymptomatic patients, the INDICAID rapid test demonstrated a PPA of 84.2% (95% CI, 69.6% to 92.6%) and an NPA of 99.9% (95% CI, 99.9% to 100%) compared to laboratory-based RT-PCR using combined nasal/oropharyngeal specimens. The INDICAID rapid test has excellent performance compared to laboratory-based RT-PCR testing and, when used in tandem with RT-PCR, reduces the time to confirmatory positive result. IMPORTANCE Laboratory-based RT-PCR, the current gold standard for COVID-19 testing, can require a turnaround time of 24 to 48 h from sample collection to result. The delayed time to result limits the effectiveness of centralized RT-PCR testing to reduce transmission and stem potential outbreaks. To address this, we conducted a thorough evaluation of the INDICAID COVID-19 rapid antigen test, a 20-minute rapid antigen test, in both symptomatic and asymptomatic populations. The INDICAID rapid test demonstrated high sensitivity and specificity with RT-PCR as the comparator method. A dual-track testing algorithm was also evaluated utilizing the INDICAID rapid test to screen for preliminary positive patients, whose samples were then prioritized for RT-PCR testing. The dual-track method demonstrated significant improvements in expediting the reporting of positive RT-PCR test results compared to standard RT-PCR testing without prioritization, offering an improved strategy for community testing and controlling SARS-CoV-2 outbreaks.

Plasmid-mediated resistance to ciprofloxacin and cefotaxime in clinical isolates of Salmonella enterica serotype Enteritidis in Hong Kong.

OBJECTIVES: To characterize the genetic determinants involved in the reduced susceptibility to ciprofloxacin and cefotaxime in Salmonella enterica serotype Enteritidis clinical isolates obtained from four patients in summer 2003 in Hong Kong. METHODS: Three Salmonella Enteritidis isolates from blood culture and one from stool were collected due to their increased resistance to ciprofloxacin and cefotaxime. PFGE analysis was used to investigate their genetic relatedness. Conjugation experiments were employed to show if the genetic determinants involved were plasmid-mediated. MICs of various antimicrobials were determined by VITEK 2 and Etest. Based on the susceptibility and conjugation experiment results, previously described PCR methods were employed to detect sequences homologous to qnr and bla(CTX-M) suspected to be involved in the reduced susceptibility to ciprofloxacin and cefotaxime, respectively. RESULTS: PFGE analysis showed that the four Salmonella isolates were clonally unrelated. The presence of a qnr-like gene and the CTX-M allele bla(CTX-M-14) on four different transferable plasmids harboured by the four isolates was confirmed. CONCLUSIONS: This is the first report of transferable fluoroquinolone resistance due to a new qnr allele, which appeared to be linked to bla(CTX-M-14), in isolates of Salmonella Enteritidis in Hong Kong.

Outcome of coronavirus-associated severe acute respiratory syndrome using a standard treatment protocol.

OBJECTIVE: There is so far no consensus on the optimal treatment strategy for the coronavirus-associated severe acute respiratory syndrome (SARS). We aimed to analyse the outcomes of a standard treatment strategy comprising antibiotics, a combination of ribavirin, a 3-week step-down course of corticosteroids, and the possibility of pulsed methylprednisolone rescue in the event of deterioration. METHODOLOGY: This was a prospective cohort study performed at a major public-funded hospital in Hong Kong. Eighty-eight World Health Organisation/Centers for Disease Control and Prevention probable cases of SARS (97% laboratory-confirmed) were treated with a standard protocol previously reported. Seventy-one patients treated de novo were analysed in detail with regard to time to clinical stabilization after combination treatment, requirement of additional therapy (pulsed methylprednisolone; assisted ventilation); and final outcomes (recovery, mortality). RESULTS: The mean age was 42. Twenty-one patients (24%) had comorbidities. Three of 71 treated de novo recovered with antibiotics alone. The remaining 68 received combination treatment at a mean of 5.8 days after symptom onset, of whom 30 subsequently required pulsed methylprednisolone rescue (independent predictors: older age and higher LDH) and 18 required assisted ventilation (independent predictors: older age, higher oxygen requirement and creatinine level). Their median time to clinical stabilization was 8.0 days after combination treatment (independent predictor for longer time to stabilization: median age of 41 or above). Common complications were hyperglycaemia (58%), pneumo-mediastinum/thoraces (13%), psychiatric manifestations (7%) and ventilator-associated pneumonia (2%). One patient (1%) died of SARS-related respiratory failure. All-cause mortality was 3.4%, occurring in patients aged > 65 years only. None of the discharged survivors required continuation of oxygen therapy. CONCLUSIONS: This standard treatment protocol resulted in overall satisfactory outcomes. Randomized controlled trial is suggested to confirm its efficacy.

Granulicatella adiacens and Abiotrophia defectiva bacteraemia characterized by 16S rRNA gene sequencing.

Traditionally, the identification, epidemiology and spectrum of clinical diseases caused by Granulicatella adiacens and Abiotrophia defectiva are dependent upon their phenotypic characterization. During a 6-year period (July 1995-June 2001), seven and two alpha-haemolytic streptococci were identified as G. adiacens and A. defectiva, respectively, by 16S rRNA gene sequencing. Three patients with haematological malignancies and neutropenic fever had primary bacteraemia. Three patients with valvular problems or congenital heart disease had infective endocarditis. A patient with ischemic heart disease and cerebrovascular accident had infected aortic atheroma with dissection. A patient with recurrent pyogenic cholangitis had acute cholangitis and a patient with polypoid cystitis and benign prostatic hypertrophy had acute prostatitis. Four of the nine patients died, including all three with G. adiacens infective endocarditis or infected atheroma. For the seven G. adiacens isolates, the API 20 STREP system successfully identified one and five isolates as G. adiacens with >95 % and 80-90 % confidence, respectively, whereas the Vitek System (GPI) and ATB Expression system (ID32 STREP) successfully identified none and one isolate as G. adiacens. Of the two A. defectiva isolates, none of the three systems successfully identified either of them as A. defectiva. 16S rRNA gene sequencing is the technique of choice for identifying G. adiacens and A. defectiva, and early surgical intervention should be considered when G. adiacens endocarditis is diagnosed.