TABLE 2.
Distribution of genetic or phenotypic characteristics of H. pylori from Calcutta in relation to disease status
| Trait or markerb | Patient disease statusa
|
|
|---|---|---|
| Peptic ulcer | Gastritis only | |
| Mtzrc | 49/55 | 17/18 |
| cag PAI+ onlyd | 46/55 | 18/23 |
| cag PAI+,− mixedd | 7/55 | 4/23 |
| cag PAI− onlyd | 2/55 | 1/23 |
| vacAs1 only | 49/55 | 18/23 |
| vacAs2 only | 2/55 | 1/23 |
| vacAs1, -s2 mixed | 4/55 | 4/23 |
| vacAm1c only | 31/55 | 12/23 |
| vacAm2 only | 19/55 | 8/23 |
| vacAm1c, -m2 mixed | 4/55 | 3/23 |
| iceA1e | 32/55 | 16/23 |
| iceA2 | 21/55 | 5/23 |
| iceA1, iceA2 mixed | 1/55 | 2/23 |
| IS605f | 16/55 | 3/18 |
| IS606 | 11/55 | 2/18 |
| IS.Inv | 10/55 | 4/18 |
Number with trait/number scored.
Distribution of DNA markers was determined by PCR or hybridization, as illustrated in the figures.
Resistant to 8 μg of MTZ/ml in agar dilution test. Four of the seven strains that were unable to grow on medium with 8 μg of MTZ/ml grew on medium with just 3 μg of MTZ/ml, indicating leaky resistance phenotypes (see text). The possibility that many of these Mtzr infections were mixed and contained only a small fraction of Mtzr cells and many Mtzs cells (as was common in a Peruvian population) (12) was tested by streaking representative Mtzr cultures on MTZ-free medium: Two single colonies from each of 10 such cultures were found to be Mtzr, whereas each of the two single colonies from an 11th Mtzr culture was Mtzs. This suggests that, despite occasional Mtzs Mtzr mixed infections, the majority of cells in most nominally Mtzr infections in Calcutta are indeed Mtzr.
cag PAI+ only, infection with strains carrying cag PAI only; cag PAI+,− mixed, mixed infection with strains carrying the cag PAI and strains lacking the cag PAI; cag PAI− only, infection with strains lacking the cag PAI only.
Just one culture failed to give iceA1 or iceA2 amplification. Of the 10 iceA1 genes (of 44 tested) that contained the 94-bp deletion (Fig. 6) not found in H. pylori from any other region studied to date, 8 were from ulcer patients and 2 were from gastritis-only patients.
Thirty-three of the 73 cultures contained just one type of mobile element, 5 cultures contained two of them, 1 culture contained all three elements, and 34 cultures lacked all three elements. Tests of 8 single colonies from each of 11 cultures carrying IS606 and each of 10 carrying IS.Inv (in total, 88 and 80 single colonies, respectively) identified these elements in every case, indicating that these estimates, based on hybridization to pools of H. pylori cultured from individual biopsies, are probably accurate.