Asunto(s)

RESUMEN

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.

RESUMEN

SETTING: GxAlert is an automatic electronic notification service that provides immediate Xpert® MTB/RIF testing results. It was implemented for the notification of patients with rifampicin resistant-tuberculosis (RR-TB) at Port Moresby General Hospital, Port Moresby, Papua New Guinea, in May 2015. OBJECTIVE: To determine if there were differences in pre-treatment attrition, the time to treatment initiation and patient outcomes in the 12 months pre- and post-introduction of GxAlert for RR-TB patients. DESIGN: This was a retrospective cohort study. RESULTS: The median time from Xpert testing to treatment initiation decreased from 35 days [IQR 13-131] prior to GxAlert to 10 days [IQR 3-29] after GxAlert (P = 0.001), with the cumulative proportion of patients initiating treatment within 30 days increasing from 25% (95%CI 17-37) to 54% (95%CI 44-64; P < 0.001) over these periods. However, our analysis of the time to treatment prior to the introduction of GxAlert suggests that a decrease had already occurred prior to implementation. There was no difference in interim clinical outcomes between the periods. CONCLUSION: Although a decrease in time to treatment initiation cannot be attributed to GxAlert, there was a significant improvement over the 2-year period, suggesting that considerable improvements have been made in timely RR-TB patient management in Port Moresby.

RESUMEN

Human immunodeficiency virus (HIV) is a significant public health issue in Papua New Guinea (PNG). After heterosexual transmission (90%), the second most common route of transmission is vertically from mother to child (3.5%). Before the introduction of molecular methods of HIV testing in PNG, diagnosing exposed infants was problematic because there were no reliable assays available for accurate early infant HIV detection. This study aimed to validate and assess a global gold standard for virological early infant HIV diagnosis in PNG: the AMPLICOR HIV DNA v1.5 assay (Roche) using dried blood spot (DBS) specimens. The assay was validated in three ways: by testing well-characterized DBS and kit controls and by blinded retesting of 42 patient specimens. The assay was further investigated by comparison with a serological assay. The results indicated that the assay was robust and highly reproducible using DBS and kit controls, with 100% sensitivity and specificity. Of the 42 infant DBS specimens that were retested blindly, 100% of the test results were concordant with diagnostic results. Among the 42 infant specimens tested with the Amplicor HIV DNA v1.5 assay we found that 33% of infants (n = 14) were HIV PCR positive and 67% (n = 28) negative. The earliest point of HIV detection established for this study was three months of age. This pilot study indicates that HIV-infected infants in PNG can be effectively diagnosed using virological testing and can thus be started earlier on treatment than was previously possible with serological testing.

Asunto(s)

RESUMEN

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.

Asunto(s)

RESUMEN

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).

Asunto(s)

RESUMEN

We describe three mutations of the red-cell anion exchangerband 3 (AE1, SLC4A1) gene associated with distalrenal tubular acidosis (dRTA) in families from Malaysia and Papua NewGuinea: Gly(701)-->Asp (G701D), Ala(858)-->Asp(A858D) and deletion of Val(850) (DeltaV850). The mutationsA858D and DeltaV850 are novel; all three mutations seem to berestricted to South-East Asian populations. South-East Asianovalocytosis (SAO), resulting from the band 3 deletion of residues400-408, occurred in many of the families but did not itselfresult in dRTA. Compound heterozygotes of each of the dRTA mutationswith SAO all had dRTA, evidence of haemolytic anaemia and abnormal red-cell properties. The A858D mutation showed dominant inheritance and therecessive DeltaV850 and G701D mutations showed a pseudo-dominantphenotype when the transport-inactive SAO allele was also present. Red-cell and Xenopus oocyte expression studies showed that theDeltaV850 and A858D mutant proteins have greatly decreased aniontransport when present as compound heterozygotes (DeltaV850/A858D,DeltaV850/SAO or A858D/SAO). Red cells with A858D/SAO had only 3% ofthe SO(4)(2-) efflux of normal cells, thelowest anion transport activity so far reported for human red cells. The results suggest dRTA might arise by a different mechanism for eachmutation. We confirm that the G701D mutant protein has an absoluterequirement for glycophorin A for movement to the cell surface. Wesuggest that the dominant A858D mutant protein is possibly mis-targetedto an inappropriate plasma membrane domain in the renal tubular cell,and that the recessive DeltaV850 mutation might give dRTA because ofits decreased anion transport activity.

Asunto(s)

RESUMEN

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.

Asunto(s)

Asunto(s)