**Acknowledgements**

Peptic ulcer bleeding and atrophic gastritis decreased the accuracy of *H. pylori* diagnostic test.

When atrophic changes occur in the gastric mucosa, a high percentage of endoscopic biopsy samples become negative at bacterial histology [20, 21]. During atrophy progression the density of *H. pylori* in the stomach mucosa decreases and may disappear completely during the late stages of atrophy [22]. This may explain the lower sensitivity of biopsy-based tests in the presence of atrophy: RUT, histology and culture. UBT and antigen stool detection can also give false-negative results in this situation. Serology is the only diagnostic method not influenced by a lower density of microorganism, being reliable even in advanced gastric body atrophy. Maastricht guidelines updates have reserved serology for special situations, including extensive atrophy of the stomach mucosa, in conditions in which the other tests may be

In childhood, advanced gastric atrophy is rare. We found only one case with atrophy, but the *H. pylori* culture was positive. It was an adolescent, 17 years and 8 months old, with a long history of illness (2 years) and with previous treatment failure. We could not find, in this case, antibiotic resistance to amoxicillin, clarithromycin, metronidazole and levofloxacin, and we suppose that the noncompliance to therapy is the cause of failure for bacterial eradication. Successful eradication is important to prevent the development of antibiotic resistance, as well as to reduce the number of treatments and procedures. Among children receiving the triple standard therapy regimen, eradication rate is declining [23]. In part, this decrease can be attributed to increased antibiotic resistance. Other reasons for treatment failure are, among others, host genetic factors, *H. pylori* virulent factors, inadequate compliance to therapy or insufficient

duration of therapy and, not in the last row, smoking and household crowding [23].

The sensitivity of histology in our study was 96.55%, while the specificity was 90.90%.

The sensibility and specificity of haematoxylin and eosin stain have been reported as 69–93% and 87–90%, respectively. The specificity can be improved to 90–100% by using special stains such as Giemsa stain, Warthin-Starry silver stain, Genta stain and immunohistochemical stain [15, 20, 21]. Immunohistochemical stain has a particular advantage in patients partially treated for *H. pylori* gastritis, a setting can result in atypical (including coccoid) forms, which may mimic bacteria or cell debris on haematoxylin and eosin preparation. The major advantages of immunohistochemical stain include shorter screening time and high specificity because it

In our study, we analysed the sensibility and specificity of histology in *H. pylori* infection, not focusing on the ones specific for the different types of stain. We used in all cases haematoxy-

Histology is an excellent method for detecting *H. pylori* infection. Haematoxylin-eosin, with or without Giemsa stains, is usually adequate. It is difficult to use culture method alone as routine diagnostic method. In our study, the specificity of histology in identifying *H. pylori* infection was 90.90%, and its sensitivity was 96.55%. Bacterial culture had the same specificity

The histology was found to be a reliable test in the presence of bleeding [19].

negative because of low bacterial density.

88 Histology

can exclude other similar-shaped organisms [15, 21].

lin-eosin stain and in a few cases Giemsa stain.

**5. Conclusions**

The authors thank Dr. Violeta Cristea and Dr. Augustina Enculescu for their laboratorial and histological support, respectively.
