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A comparison of endoscopic findings from H. pylori isolates and their virulence factors
Fowora MA, Breithaupt U, Otegbayo A, Akere A, Onyekwere C, Ndububa D, Abdulkareem FB, Lesi OA, Anomneze EE, Seriki A, Adeleye A, Omonigbehin EA, Bamidele M, Mbacha M, Müller S, Haas R and Smith SI.
Nigerian Institute of Medical Research, Yaba, Lagos, UCH, Ibadan, OAUTHC ILE-IFE, LUTH, UNILAG,
LASUTH, Lagos, NIGERIA and Munich, GERMANY.
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SUMMARY: Helicobacter pylori is the causative agent of gastritis, peptic ulcer disease as well as risk factor for gastric cancer development. The study presents the diversity of H. pylori genotypes and their association with different endoscopic findings amongst patients presenting with dyspepsia in various hospitals in Nigeria.
Out of a total of 83 isolates, patients presenting with superficial mucosal lesions had the highest isolation of H. pylori (50.6%). Few cases were reported as ulcer and cagA gene was positive in all the cases and majority of cases had dupA2 gene confirmed. No vacAs2/m1 nor s2/m2 was reported in our study
The study showed that the present of cagA gene is associated with increased risk of peptic ulcer disease although the cagA gene was positive in majority of cases irrespective of their endoscopic findings.
BACKGROUND AND AIM
Helicobacter pylori is the causative agent of gastritis, ulcer and is a risk factor in the development of gastric cancer (Blaser et al. 1995). H. pylori infects up to 50% of the human population worldwide . In Africa, H. pylori is known to be commonThe study is aimed at comparing the endoscopic findings from isolated H. pylori in Nigeria with their virulence factors.
METHODS
A total of 83 isolates of H. pylori were screened for their virulence factors using PCR for cagA, vacA and dupA genes and compared with their stomach endoscopic findings. Endoscopic findings included: (i) normal mucosa, (ii) superficial mucosal lesions, (iii) duodenal ulcers (DU) and (iv)polyp depression.
RESULTS:
The highest number of isolates was from those subjects with superficial mucosal lesions (50.6%) followed by those with normal endoscopic findings (36.1%), then from ulcer cases (9.6%) and lastly polyp (2.1%). All subjects with ulcer were found to be positive for cagA, vacAm1, s1, while 80% were positive for the dupA genes. Those with normal endoscopic finding showed cagA (82.1%), vacA s1b (86.2%), m1 (72.4%) and dupA2 (34.5%). The highest number of dupA2 positive patients were amongst those with ulcer (80%), and polyp (100%).
DISCUSSION AND CONCLUSION 
The results shows a high percentage of isolates were positive for the virulence genes irrespective of their endoscopic findings. In addition, this is the first report of dupA genes in Nigerian isolates for which majority were dupA2. Only two (2.4%) of the isolates were positive for both dupA1 and dupA2 and were from subjects presenting with superficial mucosal lesion. The higher percentage of dupA2 genes (100%) in the polyp could be understood based on the fact that only two of the patients presented with the endoscopic findings with both positive. Although a large number of studies have shown increased risk of gastric cancer (GC) in people with cagA positive H. pylori, there were no isolates from GC cases and overall cagA gene was positive in 87.8% of the isolates. The dupA gene is a risk marker for duodenal ulcer (DU) development and a protective factor against GC, there was no GC case in our study however dupA was positive in 41.3%.
Generally, the distribution of cagA was more in subjects presenting with ulcer (100%) when compared with normal endoscopic findings although still high (82.1%). This was corroborated in a previous study by Matsunari et al. (2011) where there was higher cagA positive H. pylori amongst the ulcer and gastric cancer cases (90.4 – 95.8%). This further goes to buttress the fact that the presence of cagA is associated with an increased risk of peptic ulcer disease. There was no gastric cancer case reported amongst our isolates.
In Gambia the predominant allele was the s1 and this was age dependent as those within the age groups 30 – 40 had the most virulent genotype most common (Secka et al. 2011).
No vacAs2/m1 nor s2/m2 was detected in our isolates this is in contrast with the North African study which is predominantly vacAs2 type (Al Qabandi et al. 2005), s2m2 was also predominant in another Moroccan study (Boukhris et al. 2012). This is similar to a study by Tanih et al. 2010) from South Africa where the s1m2 and s2m2 genotypes were the most common allelic combinations of the vacA genes amongst the isolates.
LITERATURE CITED
Secka O, Antonio M, Tapgun M, Berg D, Bottomley C, Thomas V, Walton R, Corrah T, Adegbola RA and Thomas JE (2011). PCR-based genotyping of Helicobacter pylori of Gambian children and adults directly from biopsy specimens and bacterial cultures. Gut Pathogens 3:5; doi: /1757 –
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3. Matsunari O, Shiota S, Suzuki R, Watada M, Klnjo N, Murakami K, Fujioka T, Kinjo F, Yamaoka Y (2011). Association between Helicobacter pylori virulence factors and Gastroduodenal diseases in Okinawa, Japan. JCM 50: 876 – 883.
4. Boukhris SA, Benajah DA, El Rhazi K, Ibrahimi SA, Nejjari C, Amarti A, Mahmoud M, El Abkari M, Souleimani A, Bennani B. (2012). Prevalence and distribution of Helicobacter pylori cagA and vacA genotypes in the Moroccan population with gastric disease. Eur J Clin Microbiol Infect Dis 31: 1775 – 81.
5. Tanih NF, McMillan M, Naidoo N, Ndip LM, Weaver LT, Ndip RN (2010). Prevalence of Helicobacter pylori vacA, cagA and iceA genotypes in South African patients with upper gastrointestinal diseases. Acta Trop 116: 68 – 73.
This study was supported by a grant from the Deutsche Forschungsgemeinschaft (DFG Africa Infectiology Initiative)to R. Haas and S. Smith