Drug-resistant tuberculosis diagnosis since Xpert® MTB/RIF introduction in Papua New Guinea, 2012-2017.

SETTING: Xpert® MTB/RIF was introduced in Papua New Guinea in 2012 for the diagnosis of tuberculosis (TB) and of rifampicin-resistant TB (RR-TB), a marker of multi-drug-resistant TB (MDR-TB). OBJECTIVE: To assess the concordance of Xpert with phenotypic drug susceptibility testing (DST) performed at the supranational reference laboratory and to describe the patterns of drug-resistant TB observed. DESIGN: This was a retrospective descriptive study of laboratory data collected from April 2012 to December 2017. RESULTS: In 69 months, 1408 specimens with Xpert results were sent for mycobacterial culture and DST; Mycobacterium tuberculosis was cultured from 63% (884/1408) and DST was completed in 99.4%. The concordance between Xpert and culture for M. tuberculosis detection was 98.6%. Of 760 RR-TB cases, 98.7% were detected using Xpert; 98.5% of 620 MDR-TB cases were identified using phenotypic DST. Phenotypic resistance to second-line drugs was detected in 59.4% (522/879) of specimens tested, including 29 with fluoroquinolone resistance; the majority were from the National Capital District and Daru Island. CONCLUSION: The high concordance between phenotypic DST and Xpert in identifying RR-TB cases supports the scale-up of initial Xpert testing in settings with high rates of drug resistance. However, rapid DST in addition to the detection of RR-TB is required.

Total lymphocyte counts in adult HIV/AIDS patients in Port Moresby General Hospital.

We carried out a prospective study of total lymphocyte counts in 124 adult patients who were diagnosed with HIV (human immunodeficiency virus) infection and/or AIDS (acquired immune deficiency syndrome) and were admitted to Port Moresby General Hospital (PMGH) from January to June 2003. The median and mean values of lymphocyte counts in these patients were found to be 0.7 x 10(9)/l and 0.9 x 10(9)/l, respectively, with a standard deviation of 0.7, both of which counts are significantly lower (p < 0.0001) than those found in members of a control population who were well and HIV-antibody-negative. We found that the lower the total lymphocyte count, the more clinically advanced was the HIV disease state. Haemoglobin values were also significantly lower in these patients. For 35% of these patients, tuberculosis was the principal diagnosis made upon being admitted. An apparent 11% of the patients who had a clinical suspicion of AIDS were HIV-antibody-negative. Total lymphocyte count methods could be used in developing countries that do not have appropriate facilities for CD4 count and viral load assays in order to monitor the patient's disease state and progression towards AIDS.

Leukaemia in children in Papua New Guinea: an unusual pattern.

We report data on 110 children aged <15 years diagnosed with leukaemia during two periods covering 13.25 years. The data sets were consistent. The reported incidence of leukaemia was low. Only 34 (31%) of the children were diagnosed with acute lymphoblastic leukaemia (ALL) compared with 54 (49%) children with acute myeloid leukaemia (AML). The overall mean (SD) age was 6.6 (3.5) years, 6.1 (3.5) for ALL and 6.9 (3.5) for AML. There was no evidence of an early childhood peak of ALL. The male : female ratio was 1.2 : 1 for all leukaemias, 1.3 for ALL and 1.25 for AML. Only eight (22%) of those diagnosed with ALL were classified as type L1. Our figures reflect a relative absence of the common (cALL) cell type in early childhood leukaemia and support the role of infection and its effect on the immune system in the aetiology of childhood leukaemia. Our data also revealed an unusually high proportion of chronic myeloid leukaemia (CML).

Antenatal screening for HPA-1a by flow cytometry.

Pregnant women who attended antenatal clinics at King George V Hospital, the Birth Centre or were referred by obstetricians from February 19 July, 1996 were screened for the platelet antigen HPA-1a by flow cytometry. Forty out of 2,300 (1.7%) were found to be negative for this antigen. Of the 28 women followed throughout their pregnancy, none developed antibody to HPA-1a. Platelet counts performed on samples from 17 babies born to 17 of these mothers were all normal. This study proves the simplicity and rapidity of flow cytometry for platelet antigen screening. The results were comparable with the Solid Phase Red Cell Adherence (SPRCA) method and with PCR. The lack of a plentiful supply of specific antibody and the rarity of fetomaternal alloimmune thrombocytopenia (FMAIT) argue against the introduction of routine screening for maternal HPA-1a status at the present time.