Risk Factors and Associated Outcomes of Virulence Genes eae, entB, and pipD Carriage in Escherichia coli, Klebsiella pneumoniae, and Salmonella spp. From HIV-1 and HIV-Negative Gastroenteritis Patients in the Dschang Regional Hospital Annex.

Background Enterobacteriaceae is one of the main families of gram-negative bacilli responsible for serious infections in humans. The severity of infection by these bacteria is a product of many factors, including virulence properties and antimicrobial resistance. This severity may be further intensified if there is an association between these factors and a depressed immune system, such as in HIV patients. This study aimed to determine the distribution of representative virulence genes among key Enterobacteriaceae isolates from HIV-1 and non-HIV gastroenteritis patients and the relationship between carrying these virulence genes and antimicrobial susceptibility, seropositive status, and severity of symptoms associated with Enterobacteriaceae infections in Dschang Regional Hospital Annex. Methodology A total of 200 gastroenteritis patients (100 HIV-1 and 100 non-HIV patients) were selected and evaluated for symptoms associated with gastroenteritis. Stool samples were obtained and cultured, from which Escherichia coli, Klebsiella pneumoniae, and Salmonella spp. isolates were obtained. Antibiotic susceptibility tests were performed on the isolates by agar disc diffusion using commonly used antibiotics. These isolates were tested for the possession of virulence genes by polymerase chain reaction (PCR); eae for E. coli, entB for K. pneumoniae, and pipD for Salmonella spp. Correlation tests and risk assessments were performed between the presence of virulence genes, antibiotic resistance, and specific symptoms. Results The isolates obtained from HIV-positive and HIV-negative patients were, respectively, 61 against 62 for E. coli, 10 against 21 for K. pneumoniae, and 11 against 15 for Salmonella spp.These organisms showed the highest resistance to amoxicillin and clavulanic acid, while the least resistance was observed against ofloxacin, gentamicin, and amikacin in both groups of patients. The virulence genes showed a generally higher occurrence in isolates from HIV-negative patients than HIV-positive patients, with the eae gene 5/61 (8.20%) against 12/62 (19.35%), the entB gene 4/10 (40.00%) against 14/21 (66.66%), and the pipD gene 5/11 (45.45%) against 7/15 (46.46%) in HIV-positive and negative patients, respectively. There was a significant correlation between eae gene carriage and resistance against imipenem (p = 0.047), gentamycin (p = 0.047), and doxycycline (p = 0.029); entB gene carriage and resistance toward levofloxacin (p = 0.017) in K. pneumoniae; and pipD gene carriage and resistance against levofloxacin (p = 0.039), imipenem (p = 0.041), and doxycycline (p = 0.042). The carriage of the virulence genes was seen to be a stronger risk only for the resistance of K. pneumoniae to ceftriaxone (odds ratio (OR) = 2.286) and gentamycin (OR = 3.000), and Salmonella spp. against imipenem (OR = 2.750) and doxycycline (OR = 2.118). The development of severe symptoms correlated significantly with virulence gene carriage in isolates, mainly in HIV-positive patients with eae (p = 0.017) and pipD (p = 0.025), with a strong risk association with the pipD gene (OR = 2.665). Conclusions Antibiotic resistance was associated with virulence gene carriage, indicating that virulence and antibiotic resistance can associate their effects and contribute to poor outcomes in the treatment of bacterial diseases in HIV patients. The possession of virulence genes increased the severity of symptoms associated with gastroenteritis in HIV-positive patients.

Molecular characterization of antimicrobial resistance related genes in E. coli, Salmonella and Klebsiella isolates from broilers in the West Region of Cameroon.

BACKGROUND: Antibiotic resistance has become an enduring threat to human health. This has prompted extensive research to identify the determinants responsible in a bid to fight the spread of resistance and also develop new antibiotics. However, routine procedures focus on identifying genetic determinants of resistance only on phenotypically resistant isolates. We aimed to characterise plasmid mediated resistance determinants in key Enterobacteriaceae isolates with differential phenotypic susceptibility profiles and evaluated the contribution of resistance genes on phenotypic expression of susceptibility. METHODS: The study was carried out on 200 Enterobacteriaceae isolates belonging to the genera E. coli, Salmonella, and Klebsiella; 100 resistant and 100 susceptible to quinolones, aminoglycosides, and ESBL-producing as determined by disk diffusion. Reduced susceptibility in susceptible isolates was determined as an increased MIC by broth microdilution. Plasmid-borne resistance genes were sought in all isolates by endpoint PCR. We performed correlations tests to determine the relationship between the occurrence of resistance genes and increased MIC in susceptible isolates. We then used the notion of penetrance to show adequacy between resistance gene carriage and phenotypic resistance as well as diagnostic odds ratio to evaluate how predictable phenotypic susceptibility profile could determine the presence of resistant genes in the isolates. RESULTS: Reduced susceptibility was detected in 30% (9/30) ESBL negative, 50% (20/40) quinolone-susceptible and 53.33% (16/30) aminoglycoside-susceptible isolates. Plasmid-borne resistance genes were detected in 50% (15/30) of ESBL negative, 65% (26/40) quinolone susceptible and 66.67% (20/30) aminoglycoside susceptible isolates. Reduced susceptibility increased the risk of susceptible isolates carrying resistance genes (ORs 4.125, 8.36, and 8.89 respectively for ESBL, quinolone, and aminoglycoside resistance genes). Resistance gene carriage correlated significantly to reduced susceptibility for quinolone and aminoglycoside resistance genes (0.002 and 0.015 at CI95). Gene carriage correlated with phenotypic resistance at an estimated 64.28% for ESBL, 56.90% for quinolone, and 58.33% for aminoglycoside resistance genes. CONCLUSIONS: A high carriage of plasmid-mediated genes for ESBL, quinolone, and aminoglycoside resistance was found among the Enterobacteriaceae tested. However, gene carriage was not always correlated with phenotypic expression. This allows us to suggest that assessing genetic determinants of resistance should not be based on AST profile only. Further studies, including assessing the role of chromosomal determinants will shed light on other factors that undermine antimicrobial susceptibility locally.

Aetiology and risk factors of bacterial gastroenteritis among febrile outpatients at the Dschang District Hospital, West Region of Cameroon: a cross-sectional study.

OBJECTIVES: To investigate the bacterial aetiologies and associated risk factors of gastroenteritis among typhoid suspected cases. DESIGN: Cross-sectional study. SETTING: This study was conducted at Dschang District Hospital of the Menoua Division, West Region of Cameroon, between April-November 2019 and June 2020. PARTICIPANTS: Participants aged ≥2 years (mean 34±18.77 years) and of both sex suspected of having typhoid fever were included, while non-suspected typhoid cases were excluded. Self-reported sociodemographic and health information at recruitment was obtained from 556 participants. METHODS: Collected stool samples were examined macroscopically and microscopically and subjected to culture. After culture, Gram staining was performed, followed by biochemical testing and characterisation using the Analytical Profile Index (API-20E) test kit. INTERVENTIONS': No intervention was done during the period of study. OUTCOME MEASURES: We identified bacterial causing gastroenteritis, and associated risk factors calculated using binary regression, adjusting for sociodemographic and health variables. RESULTS: Of 556 patients, 74.28% tested positive for gastroenteritis. Among pathogens responsible for gastroenteritis, Escherichia coli was found to be the main cause (21.1%), followed by Salmonella typhi (10.4%), Citrobacter diversus (8.2%), and Proteus mirabilis (8.2%), Proteus vulgaris (7.3%), whereas Citrobacter spp and Yersinia enterocolitica were less represented among pathogens causing the disease among patients. A significant difference (p=0.002) was observed between abdominal pain and all the micro-organisms isolated from the patients. Patients having primary level of education were significantly associated (p=0.017; 3.163 (95% CI 1.228 to 8.147)) with the prevalence of gastroenteritis. Consumption of beverages (Wald statistic: 4.823; OR: 2.471; 95% CI (1.102 to 5.539); p=0.028), use of modern toilet (Wald statistic: 4.471; OR: 1.723; 95% CI (1.041 to 2.852); p=0.034) were strongly associated with gastroenteritis and rearing of bird (Wald statistic: 4.880; OR: 0.560; 95% CI (0.335 to 0.937); p=0.027), was found to be protective. CONCLUSION: Acute bacterial gastroenteritis is a significant cause of morbidity in Dschang, with the prevalence of 74.28%. Many pathogens accounted for gastroenteritis, and E. coli (21.1%) could be a major cause, followed by S. typhi (10.4%), C. diversus (8.2%), P. mirabilis (8.2%), P. vulgaris (7.3%), whereas Citrobacter spp and Y. enterocolitica were less represented. Gastroenteritis was highly associated with primary level of education, consumption of beverages, use of modern toilet while rearing of birds was unexpectedly found to be protective against Gastroenteritis. Further characterisation is planned.

A Cross-Sectional Comparative Study of the Performance of the Widal Test and the Typhidot Immunoassay for Typhoid Fever Diagnosis in the West Region of Cameroon.

BACKGROUND: The diagnosis of typhoid fever based on the Widal slide agglutination test remains a major hurdle in developing countries due to varied perceptions of the value of the Widal test in determining clinical decision-making. We undertook a study to evaluate the diagnostic performance of the Widal test and the Typhidot immunoassay in patients suspected of having typhoid fever in the Menoua division, West Region of Cameroon. METHODS: Blood and stool samples were collected from 558 consenting febrile patients on the basis of suspicion of typhoid fever. These patients attended three district health services of the Menoua division between April 2018 and September 2019. These patients had clinical symptoms suggestive of typhoid fever as determined by their consultant. Serum was used for the Widal slide agglutination test and for the Typhidot rapid immunoassay test based on manufacturer's guidelines. A composite reference of fever plus positive coproculture for Salmonella typhi and Salmonella paratyphi was used as the reference. The sensitivity, specificity, and predictive values of the positive and negative tests were calculated as well as Cohen's kappa for agreement between the two tests. RESULTS: Of 558 patients, 12.90% tested positive for the reference method, 57.17% tested positive for the Widal slide agglutination test, while 15.59% were positive for Typhidot-IgM. The overall sensitivity, specificity, and predictive values of the positive and negative tests were 80.56%, 94.03%, 66.6%, and 97.03% for Typhidot-IgM and 94.44%, 48.35%, 21.32%, and 98.33% for the Widal slide agglutination test, respectively. Cohen's kappa estimates were 0.1660 (0.121-0.211) and 0.386 (0.312-0.460) for the Widal test and Typhidot immunoassay for 53.6% and 76.16% agreements of all observations, respectively. CONCLUSION: The Widal test was found to have a lower predictive value for the diagnosis of typhoid fever in our setting. However, the Typhidot test, although better, was not ideal. Diagnosis of typhoid fever should therefore rely on adequate clinical suspicion and a positive Typhidot test to improve the clinical management of typhoid fever in our setting.