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Canadian Journal of Infectious Diseases and Medical Microbiology publishes original research articles, review articles, and clinical studies related to infectious diseases of bacterial, viral and parasitic origin.
Canadian Journal of Infectious Diseases and Medical Microbiology maintains an Editorial Board of practicing researchers from around the world, to ensure manuscripts are handled by editors who are experts in the field of study.
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Single Nucleotide Polymorphisms in IFN-γ Signaling Pathway Associated with Risk of Hepatitis B Virus Infection in Chinese Children
Hepatitis B virus (HBV) infection is a challenging public health problem in China and worldwide. Mother-to-child transmission is one of the main transmission routes of HBV in highly endemic regions. However, the mechanisms of HBV perinatal transmission in children have not been clearly defined. The aim of this study was to demonstrate the association between single-nucleotide polymorphisms (SNPs) in IFN-γ signaling pathway and HBV infection or breakthrough infection in children. Two hundred and seventy-four HBV-infected children defined as test positive for hepatitis B surface antigen (HBsAg) and 353 controls defined as negative for HBsAg in China were recruited from October 2013 to May 2015. SNPs in IFN-γ signaling pathway including IFNG, IFNGR1, IFNGR2, and IL12B were genotyped. Rs2234711 in IFNGR1 was significantly associated with HBV infection in children (OR = 0.641, 95% CI: 0.450–0.913). In addition, rs2234711 was also significantly associated with HBV breakthrough infection in children born to HBsAg-positive mothers (OR = 0.452, 95% CI: 0.205–0.998). Our study confirmed that genetic variants in IFN-γ signaling pathway have significant associations with HBV infection, especially with HBV breakthrough in children. This study provides insight into HBV infection in children and could be used to help design effective strategies for reducing immunoprophylaxis failure.
Comparative Study of Clostridium difficile Clinical Detection Methods in Patients with Diarrhoea
Objectives. The aim of this study was to evaluate the clinical application of three methods for detecting Clostridium difficile in fecal samples. Methods. One hundred and fifty fecal specimens were collected and tested for C. difficile using three methods: (1) the toxigenic culture (TC); (2) the VIDAS enzyme immunoassay (EIA): the VIDAS glutamate dehydrogenase (GDH) assay and toxin A/B assay were used to detect GDH antigen and A/B toxin; and (3) the GeneXpert PCR assay. The toxigenic culture was used as a reference to evaluate the performance of the VIDAS EIA and the GeneXpert PCR assay. Results. Of 150 specimens, 26 carried both A and B toxin genes, and none of the samples were positive for the binary toxin gene. Toxin-producing C. difficile was found in 17.3% (26/150) of the samples. Thirty-seven GDH-positive samples were detected using the VIDAS GDH assay, and 15 toxin-positive samples were detected using the VIDAS toxin A/B assay. The GeneXpert PCR assay was used to detect C. difficile in 79 specimens simultaneously, and a total of 18 positive specimens were detected. Conclusion. The VIDAS GDH assay is useful for initial screening of C. difficile. The GeneXpert PCR assay is a simple and quick method.
Prevalence and Associated Risk Factors of Salmonella, Shigella, and Intestinal Parasites among Food Handlers in Motta Town, North West Ethiopia
Background. Intestinal parasite, Salmonella, and Shigella infections are the main public health concerns in the world, especially in developing countries due to inaccessibility of safe water and unhygienic food handling practices of food handlers. Methods. A cross-sectional study was conducted in food handlers in Motta town, from February 2019 to April 2019. The study was undertaken to determine the prevalence and associated risk factors of Salmonella, Shigella, and intestinal parasites among 243 food handlers. Sociodemographic and risk factors were collected using pretested structured questionnaire. The stool sample was collected and examined with direct wet mount and concentration techniques. Culture was performed using xylose lysine deoxycholate agar and MacConkey agar and biochemical tests like Klinger iron agar (KIA), lysine iron agar (LIA), Simmons citrate agar, sulphide indole motility test, citrate utilization, and urease production test were conducted to isolate Salmonella species and Shigella species. An antibiotics susceptibility test was performed with Mueller-Hinton agar using the disk diffusion method. Data were entered using statistical package Epi-Data Version 3.1 and analysed with logistic regression using SPSS version 25 and Fisher’s exact test. A p value < 0.05 at 95% CI was considered as statistically significant. Results. The prevalence of intestinal parasite, Salmonella, and Shigella was 27.6%, 2.5%, and 1.6%, respectively, and hookworm was the predominant intestinal parasite detected in the stool. Antimicrobial resistance was observed in ampicillin and tetracycline (100%) in Salmonella species and Shigella species. Risk factors like fingernail status, fruit washing before eating, cleaning utensils, and regular shoe wearing habit were associated with intestinal parasite, whereas fingernail status and wearing kitchen gown during food service were significantly associated with Salmonella and Shigella infections. Conclusion. The prevalence of intestinal parasitic infections, Salmonella, and Shigella infections in this study indicates the importance of food handlers as probable sources of enteropathogenic infections. Food handlers should have follow-up on the order of food safety rules and keep their personal hygiene. Hotel owners are responsible to control the health status and their created awareness by given food hygiene training for food handlers. Therefore, policy-makers and implementers should focus on the risk factors to reduce the prevalence below the level of public health importance.
Quantitative Anti-HBc in Liver Pathological States in Patients with Chronic Hepatitis B Virus Infection
Background. Changes of hepatitis B core antigen antibody (anti-HBc) in liver pathological involvement in patients with chronic hepatitis B virus (HBV) infection have not been investigated in detail. This study aimed to explore evolving patterns of anti-HBc following liver pathological states and to investigate validities of anti-HBc for predicting liver pathological states. Methods. 254 HBeAg-positive and 237 HBeAg-negative patients with chronic HBV infection were enrolled. Liver pathological diagnoses referred to Scheuer standard, and anti-HBc was measured using chemiluminescence microparticle immunoassay. Results. Anti-HBc was significantly positively correlated with pathological grades and stages in both HBeAg-positive (rs = 0.312, , and rs = 0.268, ) and HBeAg-negative (rs = 0.270, , and rs = 0.147, ) patients. The medians of anti-HBc in pathological grades of G1, G2, and G3 and stages of S1, S2, S3, and S4 in HBeAg-positive patients were all significantly lower than those in HBeAg-negative patients (all ). The areas under receiver-operating characteristic curves (95% confidence interval) of anti-HBc for predicting pathological grades ≥G2 and ≥G3, and stages ≥S2 and =S4 in HBeAg-positive patients were 0.683 (0.622–0.740) and 0.662 (0.601–0.720), and 0.627 (0.564–0.687) and 0.683 (0.622–0.740), respectively, and in HBeAg-negative patients were 0.681 (0.618–0.740) and 0.702 (0.639–0.760), and 0.569 (0.503–0.633) and 0.630 (0.565–0.691), respectively. Conclusion. Following hepatic aggravation of necroinflammation and progression of fibrosis, anti-HBc increases gradually in HBeAg-positive patients and continues to increase gradually in HBeAg-negative patients, which is a useful but unsatisfactory marker for monitoring pathological states.
Virulence Factors of Clostridioides (Clostridium) difficile Linked to Recurrent Infections
From 20 to 30% of Clostridioides (Clostridium) difficile infection (CDI), patients might develop recurrence of the infection (RCDI) and, after the first recurrence, the risk of further episodes increases up to 60%. Several bacterial virulence factors have been associated with RCDI, including the elevated production of toxins A and B, the presence of a binary toxin CDT, and mutations in the negative regulator of toxin expression, tcdC. Additional factors have shown to regulate toxin production and virulence in C. difficile in RCDI, including the accessory-gene regulator agr, which acts as a positive switch for toxin transcription. Furthermore, adhesion and motility-associated factors, such as Cwp84, SlpA, and flagella, have shown to increase the adhesion efficiency to host epithelia, cell internalization, and the formation of biofilm. Finally, biofilm confers to C. difficile protection from antibiotics and acts as a reservoir for spores that allow the persistence of the infection in the host. In this review, we describe the key virulence factors of C. difficile that have been associated with recurrent infections.
Statistical Modeling of HIV, Tuberculosis, and Hepatitis B Transmission in Ghana
Most mortality studies usually attribute death to single disease, while various other diseases could also act in the same individual or a population at large. Few works have been done by considering HIV, Tuberculosis (TB), and Hepatitis B (HB) as jointly acting in a population in spite of their high rate of infections in Ghana. This study applied competing risk methods on these three diseases by assuming they were the major risks in the study population. Among all opportunistic infections that could also act within HIV-infected individuals, TB has been asserted to be the most predominant. Other studies have also shown cases of HIV and Hepatitis B coinfections. The validity of these comorbidity assertions was statistically determined by exploring the conditional dependencies existing among HIV, TB, and HB through Bayesian networks or directed graphical model. Through Classification tree, sex and age group of individuals were found as significant demographic predictors that influence the prevalence of HIV and TB. Females were more likely to contract HIV, whereas males were prone to contracting TB.