1. Introduction
Helicobacter pylori (Hp) is a micro-aerophilic and gram-negative spiral bacterium whose main reservoir is human stomach [1] . Hp infection is the most common bacterial infection in the world, affecting more than half of the world’s population [2] . Its prevalence varies from country to country and depends on the level of socio-economic development [3] . According to a recent study, the prevalence of this infection is higher in Africa (79.1%), South America (69.4%) and Asia (54.7%) while it is lower in North America (37.1%) and Oceania (24.4%) [2] . In Benin, a seroprevalence of 75.4% in urban areas (Cotonou) and 72.3% in rural areas (Pahou) were found [4] .
The risk of becoming infected with Hp changes depending on race or ethnicity, household characteristics, and geographic location [5] . Low socioeconomic conditions are associated with a high seroprevalence of Hp infection [6] .
All routes of Hp contamination are still poorly understood. However, epidemiological studies recognize certain modes of transmission, the main one being human-to-human transmission by direct contact: oral-oral or fecal-oral [7] . Indirect contamination by water sources and food is also evoked as well as more rarely an iatrogenic pathway during digestive endoscopies [7] .
Once contracted, Hp causes histologically chronic gastritis that persists throughout the life of the subject, but which remains most often asymptomatic [8] . In addition, it may be associated with a number of extradigestive manifestations [6] . Because of its involvement in pathologies such as gastric adenocarcinoma, extranodal lymphoma of the marginal areas annexed to the mucous membranes (MALT), and gastric atrophy, the World Health Organization (WHO) has classified it as a class I carcinogen [9] .
Diagnostic methods for Hp infection are numerous. They can be invasive requiring gastric biopsy or non-invasive. Among these, we have: serology by ELISA, urea breath test and the search for bacterial antigens in stool [6] . Invasive tests include rapid urease test, pathological examination, culture and gene amplification [6] .
The objective of this work was to study the epidemiological, clinical and pathological aspects of Hp infection in adults admitted to a digestive endoscopy unit at Parakou, in the northern part of Benin.
2. Patients and Study Methods
2.1. Type and Period of Study
This was a cross-sectional study with descriptive and analytical purposes. Data collection covered the period from January 2020 to September 2020.
2.2. Study Population
The study population consisted of all patients who underwent gastroscopy in the digestive endoscopy unit at the Departmental University Hospital Center of Borgou (CHUD-B) during the data collection period.
2.3. Inclusion Criteria
The study included patients aged 18 years and older who performed a gastroscopy with gastric biopsies and gave their oral consent to participate in this study.
2.4. Exclusion Criteria
Patients who could not perform pathological examination of gastric biopsies or with blood dyscrasias precluding gastric biopsies were excluded from this study.
2.5. Variable
The dependent variable was the presence of Hp on histology. The independent variables were epidemiological, clinical and paraclinical data of patients.
2.6. Sampling
The sample size was calculated using Schwartz’s formula [10] . With “N” the minimum number of subjects to be investigated; “z2” confidence level = 1.96;
“p” prevalence (89.4%) [11] ; “i” the margin of error = 5% and q = 1 − p =10.6%;
N = 146 people, in anticipation of 3% losses, N was increased to 146 + (3% of 146);
So the minimum sample size is 150 people.
Recruitment of patients meeting the inclusion criteria was comprehensive.
2.7. Medical Examinations Procedure
Gastroscopy was performed by the same hepato-gastroenterologist, without sedation, in patients who had been fasting for at least six (6) hours. Five (5) gastric biopsies were taken, including two antral at about 2 cm from the pylorus, two fundic, one at the angulus and put in different vials. The samples are immediately fixed with 10% neutral buffered formalin and then sent to the pathological anatomy laboratory with a form completed by the doctor.
It should be noted that in case of poor tolerance of gastroscopy, not all 5 biopsies were performed.
The histological examination of all samples was performed by the same pathologist assisted by two laboratory technicians. It took place in several stages including macroscopy, circulation, inclusion, microtomy, staining, assembly and microscopy.
At macroscopy, each biopsy was the subject of a macroscopic report that detailed the nature of fixative, number of fragments, dimensions, color and consistency of the biopsy. After measurement and description, the biopsy fragments were introduced into cassettes numbered according to their antral or fundic topography.
The circulation, consisted in making stay in a series of baths, the gastric biopsies put in cassettes, in order to give them rigidity by transforming them into a rigid firm tissue favoring the microtome cut. This circulation was done in three stages: 1) dehydration during which the tissue is cleared of the water it contains by following four baths of alcohol (ethanol) of increasing degree: 80˚, 90˚, 95˚ and 100˚ lasting one hour each; 2) lightening, which consisted in replacing ethanol in the tissue with xylene, and 3) impregnation, during which two paraffin baths of one and three hours respectively are performed.
Inclusion consisted of including the impregnated tissue in a block made of the inclusion medium (paraffin), melted between 55 and 60 degrees.
During microtomy, cuts of about 2 to 3 micrometers thick were made using a microtome (the Microtec CUT 4060).
The paraffin ribbons containing the biopsy tissue were spread on slides. The slides were stained with Hematoxylin and Eosin and then mounted with a special glue (Eukitt).
At microscopy and low magnification, the type of gastric mucosa (antral, fundic) was identified. At high magnification, it was specified the type of mucosa and the nature of different lesions (inflammation, activity, atrophy, intestinal metaplasia, dysplasia or even cancerization) as well as the presence or absence of Hp. The classification system for gastritis used in our study was that of Sydney.
2.8. Data Collection
Patient recruitment was done each time an upper GI endoscopy was performed. After obtaining their oral consent, patients selected for the survey were interviewed through a semi-structured interview. Paraclinical data were entered on the survey sheet as soon as the results were available.
2.9. Data Processing and Analysis
Data were recorded in Epi Data Entryclient 3.1 software. They were analyzed with Epi Data analysis 2.3 software. The significance threshold was set at 5%.
2.10. Ethical Considerations
Before this study, the protocol had obtained the agreement of the Local Ethics Committee for Biomedical Research of the University of Parakou (No. 0303/CLERB-UP/P/SP/R/SA). The patient anonymity was respected.
3. Results
3.1. Frequency of Hp Infection
Among the 151 patients included in the study, Hp was noted on histology in 78 subjects, representing a hospital frequency of 51.66%.
In 151 patients included, 146 had at least one antral biopsy and 140 had at least one fundic biopsy.
3.2. Characteristics of Patients Infected with Hp
- Socio-demographic data
The mean age of patients infected with Hp was 40.63 ± 15.32 years with the extremes of 18 and 89 years. The most represented age group was 20 to 29 years (24.36%). Forty-one (52.56%) were female, or a sex ratio of 0.90. In 78 patients infected with HP, 46 (58.97%) were educated. The average household size was 5.97 ± 3.90 with the extremes of 1 and 15. More than half (53.85%) of subjects from households of more than 4 people were infected with Hp. The monthly income was lower than the guaranteed minimum interprofessional wage (SMIG) in Benin, i.e. less than 40,000 FCFA in 47 patients infected with Hp (60.26%).
- Lifestyle data
Among the patients infected with HP, 42 (53.85%) reported daily use of potable drinking water (tap). Handwashing with soap and water was practiced by 43 people (55.13%) and after toilets by 50 people (64.10%). 63 people (80.77%) washed fruits and vegetables with simple water before consumption. In 78 patients infected with HP, 61 (78.21%) had latrines and 27 (34.61%) lived in mud or bamboo houses. Among the 78 subjects infected with HP, 75 people (96.15%) were non-smoking and 74 people (94.87%) did not take alcoholic beverages.
- Data on symptoms
Sixty-nine (88.46%) patients infected with Hp had abdominal pain, located in the epigastric region in 71.01% of cases. Early satiety was reported by 55 patients (70.51%).
- Endoscopic data
Endoscopically, 77 patients (98.72%) had erythematous gastropathy. Gastropathy was erosive or ulcerated in 15 people (19.23%). Gastric or duodenal ulcers were found in 6 subjects (7.69%).
- Histological data
All the patients infected with Hp had active chronic gastritis. As for cell atrophy, it was present in 65 infected patients (83.33%). Chronic Hp gastritis was antral in 64 patients (82.05%). Table 1 shows the distribution of patients infected with Hp according to the histological aspects of gastric biopsies.
3.3. Factors Associated with Hp Infection
In bivariate analysis, no statistically significant association was noted between
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Table 1. Distribution of Hp infected patients by histological aspects of gastric biopsies (Parakou, 2020, N = 78).
age (p = 0.830), sex (p = 0.571), socioeconomic status (p = 0.237), household size (p = 0.684), source of drinking water (p = 0.766), presence or absence of latrine at home (p = 0.691), type of dwelling (p = 0.163), alcohol (p = 0.292) or tobacco (p = 0.999) consumption and Hp infection (Table 2).
Failure to take a PPI two weeks before the examination (p = 0.040; RP = 0.68), absence of handwashing with soap and water before meals (p = 0.009; RP = 0.66), erythematosus aspect of gastritis (p = 0.023; RP = 0.37), absence of intestinal metaplasia in the fundus (p = 0.036; RP = 4.31) and active chronic gastritis (p = 0.005) were statistically associated with Hp infection, as shown in Table 3.
4. Discussion
This work has made it possible to have basic data on Hp infection in the northern part of Benin Republic. Moreover, the factors favoring this infection have been identified to better guide prevention.
The hospital frequency of Hp infection remains high in Parakou. It was 51.66%. It is close to 51.4% reported by Darré et al. [12] in 2010 in Togo. On the other hand, Doh et al. [13] in 2016 in Senegal and Essadik et al. [14] in 2011 in Morocco found a higher frequency of 75.6% and 69.2% respectively. The use in these studies of special straining including modified Giemsa which makes it possible to better visualize Hp and also the study population which included all age groups could explain this difference.
In this study, the mean age of infected patients was 40.63 ± 15.32 years. Doh
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Table 2. Relationship between Hp infection and socio-demographic, economic, environmental and lifestyle characteristics of patients (Parakou, 2020, N = 151).
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Table 3. Factors associated with Hp infection (Parakou, 2020, N = 151).
PPI = Proton Pump Inhibitor.
et al. [13] in 2016 in Senegal had found an average age close to ours (39.9 years). Our results are also similar to those of Itoudi et al. [15] in 2014 in Gabon and Hafidi et al. [16] in 2012 in Morocco, which noted a mean age of 41.9 years and 43.5 years respectively. The young age of infected patients confirms the fact that in developing countries, Hp infection is contracted at an early age. Indeed, a study conducted in the general population among children in the same city of Parakou reported a prevalence of 60.4% [17] .
In this study, the majority of patients infected with Hp had abdominal pain (88.46%) and early satiety (70.51%). The site of abdominal pain was epigastric in 71.01% of cases. In the study conducted by Doh et al. [13] in 2016 in Senegal, epigastralgia (90.2%) was the most common sign. Hafidi et al. [16] in 2012 in Morocco, meanwhile, found epigastralgia in 65.81% of cases. Abdominal pain therefore remains the main clinical manifestation of Hp infection.
In patients with erythematous, erosive or ulcerated gastropathy, 53.85%, 63.16% and 50% respectively were infected with Hp. The same observation was made in Tunisia by Jmaa et al. [18] who reported in 2005 that 93.6% of patients who had gastropathy were infected with Hp. Gastropathy on gastrointestinal endoscopy would therefore be the most common elementary lesion of Hp infection.
Among cases of chronic Hp gastritis, atrophy was noted in 83.33% of cases. These data are lower than those of Essadik et al. [14] in 2011 in Morocco who reported a chronic atrophic gastritis prevalence of 91.8% in the presence of Hp. Darré et al. [12] in 2010 in Togo noted a higher prevalence of chronic Hp gastritis cases at 99%. This difference could be explained by the inclusion in our study of patients who took a PPI or antibiotics before biopsy, thus decreasing the possibilities of visualizing Hp on histology. Indeed, this bacterium induces inflammatory and immunological responses reflecting this significant proportion of atrophy in chronic Hp gastritis. This atrophy predisposes to metaplasia during which dysplasia or even cancer may appear [19] .
In this study, living in a crowded household was not a risk factor for Hp infection (p = 0.684), whereas Ategbo et al. [20] in 2012 in Gabon and Agossou et al. [17] in 2018 in Benin, showed that overcrowding in households was a risk factor for Hp infection. This difference could be explained by the difference in the diagnostic method, in particular the detection of bacterial antigens in stool. These studies were also conducted during childhood, a period during which contamination would be greater.
This study found that taking a PPI during the last two weeks before gastric biopsy decreased the chances of visualizing HP. Indeed, patients who had not taken a PPI were more infected (57.01%) than those who had taken it (38.64%) and this difference was statistically significant (p = 0.040). This result could be explained by the inappropriate prescription of Hp eradication treatment observed in some of our patients. Indeed, most patients admitted for gastroscopy and from other hospitals had already received a PPI or even Hp eradication treatment without confirmation. This inappropriate prescription would be linked on the one hand to the limited financial means of patients to honor gastroscopy with biopsies for histopathological examination and on the other hand to the lack of technical platform necessary for the rapid diagnosis of Hp in all care facilities.
This work has shown that not washing hands with soap and water before meals is a risk factor for Hp infection. Patients who did not practice it were more infected (66.04%) and this association was statistically significant. Sagbo et al. [21] in 2018 in Benin reported that not washing hands with soap and water before meals was a risk factor for Hp infection. These results could be explained by the hand transmission of Hp infection.
As for endoscopic aspects, only patients with erythematous gastropathy were more likely to be infected with Hp (p = 0.023). Itoudi et al. [15] in 2014 in Gabon had noted that the presence of gastric endoscopic and duodenal lesions (gastropathy, gastric ulcer, duodenal ulcer) was statistically associated with Hp infection (p = 0.001). The inclusion in our study of patients who took antibiotics or a PPI before gastric biopsy could justify this difference.
Regarding pathological aspects, the presence of signs of cellular activity was significantly associated with Hp infection (p = 0.005). Our study also found an association between the absence of intestinal metaplasia in the fundus and the presence of Hp. Indeed, Hp was visualized in 54.62% of cases in the absence of intestinal metaplasia against 20% in the presence of intestinal metaplasia and this difference was statistically significant (p = 0.036). This result may justify the fact that the presence of intestinal metaplasia in the stomach is generally associated with low Hp density due to changes in mucus and gastric acidity [22] .
One of the limitations of this study is that GIEMSA staining could not be used, which could underestimate the frequency of Hp infection in hospital.
5. Conclusion
In Parakou, in the northern part of the Republic of Benin, the hospital frequency of Hp infection is high. All age groups are concerned. These infected patients often report epigastric pain. Erythematous gastropathy is the lesion most found on digestive endoscopy. As for histopathology, Hp infection is responsible for chronic active gastritis often atrophic with sometimes intestinal metaplasia or even dysplasia. Factors associated with this infection are the lack of proton pump inhibitor intake during the last two weeks prior to upper GI endoscopy, lack of handwashing with soap and water before meals, erythematous aspect of gastropathy on digestive endoscopy, absence of intestinal metaplasia in the fundus, chronic and active characteristics of gastritis on histology. Raising public awareness on the manifestations of this infection and compliance with hygiene measures will prevent complications.