LITERATURE UPDATE
RPP testing, 20 (44%) tested positive for other respiratory pathogens. Negative testing for B. pertussis and positive testing for other respiratory pathogens on RPP was common in samples that previously tested positive on dedicated B. pertussis PCR testing, both of which could lead to missed diagnoses of pertussis infection. Clinicians should consider using dedicated pertussis PCR testing if pertussis infection is suspected.
Diagnostic study of pertussis using PCR in primary care clinics
Rodríguez Arranz C, Albañil Ballesteros MªR, García Vera C, Blasco Alberdi M, Gil de Gómez MJ. An Pediatr (Engl Ed). 2022 Oct; 97 (4): 262–9.
doi: 10.1016/j.anpede.2022.02.005. Bordetella pertussis growing on charcoal agar.
the accumulation of cAMP. Apart from this classical model, PTx also activates some receptors and can affect various ADP ribosylation- and adenylate cyclase- independent signalling pathways. Owing to its potent ADP-ribosylation
properties, PTx has been used in many research areas. Initially the research primarily focused on the in vivo effects of the toxin, including histamine sensitisation, insulin secretion and leucocytosis. Nowadays, PTx is also used in toxicology research, cell signalling, research involving the blood-brain barrier, and testing of neutralising antibodies. However, the most important area of use is testing of acellular pertussis vaccines for the presence of residual PTx. In vivo models and in vitro assays for PTx often reflect one of the toxin’s properties or details of its mechanism. In this article, the established and
novel in vivo and in vitro methods used to evaluate PTx are reviewed, their mechanisms, characteristics and limitations are described, and their application for regulatory and research purposes are considered.
Can Comprehensive Respiratory Pathogen Panels be Used to Exclude Pertussis Infection? Mayhew CE, Cranford JA Newton DW, Cator AD. J Emerg Med. 2021 May; 60 (5): 591–8. doi: 10.1016/
j.jemermed.2020.10.053.
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Pertussis is a serious public health concern and accurate diagnosis is imperative. Comprehensive, multiplex respiratory pathogen polymerase chain reaction (PCR) panels (RPPs) have recently become popular, but their utility in excluding pertussis infection has not been fully explored. This study aims to determine RPP
testing results for pertussis using frozen banked samples that previously tested positive on dedicated Bordetella pertussis PCR testing, and to describe positive test rates for other respiratory pathogens on these samples via RPP. The authors’ microbiology laboratory retrieved banked nasopharyngeal samples from inpatient, ambulatory, and emergency department sources that were positive for pertussis using B. pertussis PCR testing from March 2015 to October 2017. RPP was performed on thawed, archived samples. Rate of pertussis identification on RPP was determined, and positive tests for other pathogens were tabulated.
A total of 3482 specimens were submitted for pertussis PCR testing during the study period. Of those, 138 (4%) were positive for B. pertussis, and 102 (74%) samples were banked and available for RPP testing. Fifty-seven of 102 (56%) of the banked samples had positive RPP testing for pertussis. Of the 45 samples negative for pertussis on
Pertussis is a respiratory infection caused by bacteria of the genus Bordetella, mainly pertussis and parapertussis species. Despite the high vaccination coverage in developed countries, it is considered a re-emerging disease that is also underreported and underdiagnosed, especially in patients who do not require hospital referral.
This study involved the descriptive,
prospective and multicentre study of pertussis diagnosis and contact investigation in 17 primary care paediatric clinics through collection of samples for polymerase chain reaction (PCR) testing over a period of four years and after the implementation of routine vaccination against pertussis during pregnancy.
Pertussis was diagnosed in a total of 50 patients; the estimated incidence in these years was higher compared to previous rates in the paediatric age group. Fourteen percent of the cases occurred in children aged less than one year. The mean age was 6.7 years. Cough was present in 100% of cases, followed in frequency by vomiting and rhinorrhoea. Only one patient required hospital admission, and none died or developed complications. B. pertussis was the predominant causative agent. Only 40% knew the source of infection. In 26% of the cases, pertussis was confirmed in contacts of the patient by PCR, and in 46% it was suspected based on the clinical presentation but without microbiological confirmation. Access to diagnostic tests (PCR) for pertussis in primary care makes it possible to optimise its diagnosis and treatment, to break the chain of transmission, to know the real incidence rates and to assess the impact of routine vaccination of pregnant women on this disease.
AUGUST 2024
WWW.PATHOLOGYINPRACTICE.COM
Nathan Reading from Halesowen, UK CC BY 2.0 Wikimedia Commons
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