Detection of SARS-CoV-2 infection in the general population by three prevailing rapid antigen tests: cross-sectional diagnostic accuracy study.

BACKGROUND: Rapid antigen diagnostic tests (Ag-RDTs) are the most widely used point-of-care tests for detecting SARS-CoV-2 infection. Since the accuracy may have altered by changes in SARS-CoV-2 epidemiology, indications for testing, sampling and testing procedures, and roll-out of COVID-19 vaccination, we evaluated the performance of three prevailing SARS-CoV-2 Ag-RDTs. METHODS: In this cross-sectional study, we consecutively enrolled individuals aged >16 years presenting for SARS-CoV-2 testing at three Dutch public health service COVID-19 test sites. In the first phase, participants underwent either BD-Veritor System (Becton Dickinson), PanBio (Abbott), or SD-Biosensor (Roche Diagnostics) testing with routine sampling procedures. In a subsequent phase, participants underwent SD-Biosensor testing with a less invasive sampling method (combined oropharyngeal-nasal [OP-N] swab). Diagnostic accuracies were assessed against molecular testing. RESULTS: Six thousand nine hundred fifty-five of 7005 participants (99%) with results from both an Ag-RDT and a molecular reference test were analysed. SARS-CoV-2 prevalence and overall sensitivities were 13% (188/1441) and 69% (129/188, 95% CI 62-75) for BD-Veritor, 8% (173/2056) and 69% (119/173, 61-76) for PanBio, and 12% (215/1769) and 74% (160/215, 68-80) for SD-Biosensor with routine sampling and 10% (164/1689) and 75% (123/164, 68-81) for SD-Biosensor with OP-N sampling. In those symptomatic or asymptomatic at sampling, sensitivities were 72-83% and 54-56%, respectively. Above a viral load cut-off (≥5.2 log10 SARS-CoV-2 E-gene copies/mL), sensitivities were 86% (125/146, 79-91) for BD-Veritor, 89% (108/121, 82-94) for PanBio, and 88% (160/182, 82-92) for SD-Biosensor with routine sampling and 84% (118/141, 77-89) with OP-N sampling. Specificities were >99% for all tests in most analyses. Sixty-one per cent of false-negative Ag-RDT participants returned for testing within 14 days (median: 3 days, interquartile range 3) of whom 90% tested positive. CONCLUSIONS: Overall sensitivities of three SARS-CoV-2 Ag-RDTs were 69-75%, increasing to ≥86% above a viral load cut-off. The decreased sensitivity among asymptomatic participants and high positivity rate during follow-up in false-negative Ag-RDT participants emphasise the need for education of the public about the importance of re-testing after an initial negative Ag-RDT should symptoms develop. For SD-Biosensor, the diagnostic accuracy with OP-N and deep nasopharyngeal sampling was similar; adopting the more convenient sampling method might reduce the threshold for professional testing.

Bacterial agents in vulvovaginitis and vaginal discharge: a 10-year retrospective study in the Netherlands.

Vulvovaginitis is a common problem in the GP's practice. Causes are bacterial vaginosis (BV), Candida infection and sexually transmitted infections (STIs). Only if empirical treatment fails, a vaginal swab is sent in for culture and BV detection. However, without culture essential, bacterial pathogens may escape diagnosis. Many molecular BV assays have recently appeared on the marketplace, all quite differing in price and targets. However, for years, the Nugent score has been the gold standard for BV detection. We analysed retrospectively 10 years of microbiology results of vulvovaginal swabs, focusing on less frequently reported bacterial pathogens, and assessed the characteristics of BV diagnostics. Vulvovaginal swabs sent in between 2010 and 2020 from > 11,000 GP patients with vulvovaginitis associated symptoms, but negative STI tests, were analysed. First cultures and repeat cultures after at least 6 months were included in four age groups: < 12, 12-17, 18-51 and > 51 years. Candida species and BV were most frequently found, with the highest prevalence in premenopausal women. Haemophilus influenzae, beta-haemolytic streptococci, Streptococcus pneumoniae and Staphylococcus aureus were isolated in 5.6% of all cultures, with the highest percentages in children and postmenopausal women. If empirical treatment of vulvovaginitis fails, bacterial culture should be performed to detect all potentially pathogenic microorganisms to obtain a higher rate of successful diagnosis and treatment, avoiding unnecessary antimicrobial use and costs. For BV detection, molecular testing may seem attractive, but Nugent scoring still remains the low-cost gold standard. We recommend incorporating the above in the appropriate guidelines.

Efficacy of Pre-Operative Antimicrobial Prophylaxis in Patients Undergoing Pancreatoduodenectomy: A Multi-Center Retrospective Analysis.

BACKGROUND: The most common complications after pancreaticoduodenectomy (PD) are infectious, despite the standard use of cefazolin and metronidazole prophylaxis. Pre-operative biliary drainage (PBD) is a well-known risk factor for infectious complications. The objective was to identify the pathogens in intra-operative bile cultures in patients undergoing PD-with and without PBD-to determine the optimal antimicrobial prophylaxis regimen. PATIENTS AND METHODS: Patients who underwent PD between 2009 and 2016 were identified retrospectively in three major teaching hospitals in The Netherlands. Organisms isolated from intra-operative bile cultures were studied. If pathogen coverage by standard prophylaxis was incomplete, the most appropriate alternative regimen was determined. RESULTS: Of this large cohort of 352 patients, 56% underwent PBD and 44% did not. Positive bile cultures were found in 87.9% in the PBD group, compared with 31.8% in the non-PBD group. The micro-organisms isolated most commonly were Enterococcus, Streptococcus, and Klebsiella species. Cefazolin and metronidazole were appropriate in only 71% of patients. Adding gentamicin would provide complete coverage in 99% of PBD and 100% of non-PBD patients. CONCLUSIONS: Our data confirm that PBD prior to PD leads to microbial colonization and antibiotic resistance. To potentially prevent infectious complications, gentamicin may be added to the standard antimicrobial prophylaxis.

Infectious Complications after Major Abdominal Cancer Surgery: In Search of Improvable Risk Factors.

BACKGROUND: Major resections for esophageal, gastric, hepatic, pancreatic, and colorectal cancer continue to be associated with a high peri-operative morbidity of up to 30%-40%. To a large extent, this morbidity is caused by infectious complications that add up to a considerable burden to patients and hospital costs. The objective of this large retrospective cross-sectional study was to determine independent patient and operation-related risk factors for infectious complications after major abdominal cancer operations to elucidate how infection rates can be reduced and improve health-care quality. PATIENTS AND METHODS: In 1,389 cancer patients who underwent a major resection procedure between 2009 and 2013, infectious complications and their independent determinants were analyzed by multivariable logistic regression (p < 0.05). RESULTS: Male gender was a risk factor for infections in general, whereas patients ≥65 y (odds ratio [OR] 1.75; p = 0.008), urinary tract infection (OR 0.51; p = 0.004), American Society of Anesthesiologists score (OR 1.55; p = 0.004), overall (OR 1.70; p = 0.037), vascular (OR 1.59; p = 0.020), and neurologic comorbidity (OR 2.22; p = 0.001) were associated significantly with pneumonia. Intra-abdominal drainage (OR 1.41; p = 0.024) and a duration of surgery of ≥180 min (OR 1.85; p = 0.001) were risk factors for surgical site infections. Total parenteral nutrition was significantly associated with intravascular catheter-induced infections (OR 18.09; p < 0.001) and sepsis (OR 6.69; p < 0.001). CONCLUSIONS: In this study, several independent risk factors for infectious complications in major abdominal cancer operations were identified, providing opportunities for further reducing peri-operative infections. General awareness and focus on preventing infectious complications may have a significant impact on health-care outcomes and costs.

Respiratory disease and Trichomonas vaginalis in premature newborn twins.

In premature newborn twins with respiratory disease, Trichomonas vaginalis infection was diagnosed by chance findings in respiratory samples and was confirmed by polymerase chain reaction of urine and vaginal samples from the boy and girl, respectively. Trichomonas vaginalis should be considered as a possible cause of respiratory disease in newborns and modern molecular detection techniques can help in the diagnosis.

Does electronic clinical microbiology results reporting influence medical decision making: a pre- and post-interview study of medical specialists.

BACKGROUND: Clinicians view the accuracy of test results and the turnaround time as the two most important service aspects of the clinical microbiology laboratory. Because of the time needed for the culturing of infectious agents, final hardcopy culture results will often be available too late to have a significant impact on early antimicrobial therapy decisions, vital in infectious disease management. The clinical microbiologist therefore reports to the clinician clinically relevant preliminary results at any moment during the diagnostic process, mostly by telephone. Telephone reporting is error prone, however. Electronic reporting of culture results instead of reporting on paper may shorten the turnaround time and may ensure correct communication of results. The purpose of this study was to assess the impact of the implementation of electronic reporting of final microbiology results on medical decision making. METHODS: In a pre- and post-interview study using a semi-structured design we asked medical specialists in our hospital about their use and appreciation of clinical microbiology results reporting before and after the implementation of an electronic reporting system. RESULTS: Electronic reporting was highly appreciated by all interviewed clinicians. Major advantages were reduction of hardcopy handling and the possibility to review results in relation to other patient data. Use and meaning of microbiology reports differ significantly between medical specialties. Most clinicians need preliminary results for therapy decisions quickly. Therefore, after the implementation of electronic reporting, telephone consultation between clinician and microbiologist remained the key means of communication. CONCLUSIONS: Overall, electronic reporting increased the workflow efficiency of the medical specialists, but did not have an impact on their decision-making.

Evaluation and implementation of a chromogenic agar medium for salmonella detection in stool in routine laboratory diagnostics.

We evaluated which chromogenic agar medium for Salmonella detection in stool would be most sensitive and specific in our culture protocol. The use of BBL CHROMagar Salmonella chromogenic medium combined with xylose-lysine-deoxycholate agar yielded a sensitivity of 100% and also reduced workload and costs.

Identification and susceptibility testing of Enterobacteriaceae and Pseudomonas aeruginosa by direct inoculation from positive BACTEC blood culture bottles into Vitek 2.

Inoculation of an automated system for rapid identification (ID) and antimicrobial susceptibility testing (AST) directly from positive blood culture bottles will reduce the turnaround time of laboratory diagnosis of septicemic patients, which benefits clinical outcome and decreases patient costs. Direct test results, however, must always be confirmed by testing a pure overnight culture, which is the "gold standard." We studied the accuracy of direct testing versus repeat testing in order to investigate the possibility of refraining from repeat testing. We also assessed the clinical risk of reporting results based on direct testing only. We inoculated Vitek 2 (bioMérieux) directly from 410 positive BACTEC 9240 (BD) blood culture bottles containing gram-negative rods and studied the ID and AST results. In a comparison of direct inoculation with the standard method, a total of 344 isolates of Enterobacteriaceae and Pseudomonas aeruginosa were tested, and 93.0% were correctly identified. Of the 39 (10.2%) samples that contained bacilli not identifiable by Vitek 2, only 1 gave a conclusive, correct result. The overall MIC agreement among 312 isolates was 99.2%, with 0.8% very major and 0.02% major error rates. Of only three (polymicrobial) samples, the direct susceptibility pattern would be reported to the clinician as too sensitive. Vitek 2 results obtained from direct inoculation of blood culture bottles containing gram-negative bacilli are safe enough for immediate reporting, provided that ID and AST are consistent. Repeat testing is not necessary, unless Gram stain or overnight subculture results raise doubt about the purity of the culture.