Usefulness of quantitative buffy coat blood parasite detection system in diagnosis of malaria.

A rapid test for diagnosis of malaria based on acridine orange staining of centrifuged blood samples in a microhematocrit tube (QBC) was compared with thick and thin peripheral blood smears in 2274 samples. Malaria was diagnosed in 239 (10.5%) patients by Leishman's staining technique and QBC method. The QBC method allowed detection of an additional 89 (3.9%) cases. Thus the prevalence rate of malaria during the study was 14.4%. In 1946 patients who were negative by the QBC technique, the Leishman's stained smears did not provide any help in malaria diagnosis. Analysis of the relative quantity of parasites in the specimens, in the QBC method, revealed that 80 out of 89 QBC positive but smear negative cases, had a very low parasite number (less than 10 parasites per QBC field). Although QBC method was superior to the smear for malarial parasite detection, species identification was not possible in 26 (7.9%) cases by this technique. In 95.7% (n = 314) QBC positive cases, the buffy coat in the QBC tube appeared pigmented (gray to black). The colour of the buffy coat was therefore considered by us as a predictor of positivity and could be taken as an indicator for a careful and more prolonged search for the parasites. Thus, the QBC technique has its advantages in terms of speed, sensitivity and ease, especially in an endemic area as ours, where the level of parasitaemia is low and more than 70 to 80 smears need to be examined per day. However, the age old Romanowsky stains still appear superior for species identification.

Characterization of nonfermenters from clinical samples.

OBJECTIVE: Nonfermenters are a group of aerobic non sporing gram-negative bacilli found primarily free in nature and as commensals, whose pathogenic potentials are well established. The current study was conducted to assess the role of these nonfermenters in various infections and to characterize these isolates. METHODS: One hundred nonfermenters isolated from various clinical specimens were grouped according to Weaver-Hollis scheme based on growth on MacConkeys agar, oxidase activity and oxidation/fermentation of glucose. Species level identification was attempted based on a battery of biochemical tests. All isolates were then subjected to antimicrobial sensitivity. RESULTS: Majority of the isolates were encountered from pus and urine (50%). These isolates belonged to six of the seven Weaver-Hollis groups. Fifty six per cent of the isolates belonged to genus Pseudomonas. Multidrug resistance with resistance to more than three antimicrobials was frequently seen. Amikacin and ciprofloxacin were found to be most effective. CONCLUSION: Nonfermenting gram negative organisms are responsible for variety of infective conditions. Amongst them genus Pseudomonas and Acinetobacter calcoaceticus were more frequently encountered. Amikacin or ciprofloxacin (for nonfermenters other than Pseudomonas) appears to be the drug of choice for treatment of such infections.

Rapid diagnosis of falciparum malaria by detection of Plasmodium falciparum HRP-2 antigen.

OBJECTIVE: Malaria is a resurging problem all over the country and rapid diagnosis is mandatory to decrease the morbidity and mortality and for control of malaria. In the current study the aim was to evaluate the usefulness of rapid Plasmodium falciparum antigen detection and to compare its utility over conventional peripheral thick and thin smear examination. METHODS: Three hundred fifty seven randomly selected patients with pyrexia and or atypical presentations of malaria, found initially negative for malaria were subjected to thick and thin smear examination and Plasmodium falciparum antigen detection test by using commercially available Parasight F. kit. RESULTS: 54.6% of cases presented with pyrexia, while other presentations of falciparum malaria were less frequently encountered (162/357). Eighty five patients (23.8%) were diagnosed as having falciparum malaria based on smear/Parasight F. Test. Eighty- four of these patients were positive for Parasight F. test and only 34.51% of these cases were also positive on smear examination. CONCLUSION: The antigen detection test for Plasmodium falciparum is useful for rapid diagnosis of Plasmodium falciparum malaria. It could detect 65.5% cases of falciparum malaria which were initially negative by peripheral smear examination. Hence, this technique is superior to peripheral smear staining and helps early diagnosis.

Evaluation of HBsAg carrier rate in acute viral hepatitis and high risk individuals using RPHA and ELISA.

A total of 600 individuals including 500 cases of hepatitis and 100 individuals at high risk for developing hepatitis were screened for hepatitis B surface antigen (HBsAg) using reverse passive haemagglutination (RPHA) and enzyme linked immunosorbent assay (ELISA). HBsAg carrier rate in clinically diagnosed cases of hepatitis was 38% and 32.4% by RPHA and ELISA respectively. In high risk individuals, the carrier rate was 14% by RPHA and 11% by ELISA. Taking ELISA as gold standard, RPHA showed 5.33% false positivity and 0.33% false negativity. The over all correlation between RPHA and ELISA was to the tune of 82.66%.

Bacterial pneumonias--evaluation of various sputum culture methods.

With an objective of improving diagnostic value of sputum in bacterial pneumonias, 50 uncomplicated 'community' acquired cases were studied using Gram staining of sputum along with bedside inoculation with/without dilution of the specimen. Gram staining of sputum samples collected before treatment revealed pneumococcal infection in 46% cases. The results were however inconclusive on samples sent by routine procedure involving logistic delay. Cultural analysis of sputum processed by three different techniques showed that bedside inoculation of sputum after dilution to be the most efficient technique yielding Streptococcus pneumoniae in 34% cases, Gram positive cocci in lesser number (20%), Gram negative rods (GNR) in 18% cases. Sputum samples processed bedside without dilution yielded a lower number of pneumococci and other Gram positive cocci (24% & 16% cases respectively). Routine processing of sputum, involving logistic delay yielded a high number of Gram negative rods (62%), indicating their overgrowth. Thus bedside inoculation of sputum after dilution coupled with direct Gram staining serves as a simple and yet valuable laboratory aid in the diagnosis of uncomplicated 'community' acquired bacterial pneumonias.

Salmonellosis in Goa.

During the period 1982-86, a total of 657 Salmonella strains were isolated from various clinical samples processed in the Microbiology laboratory of Goa Medical College, Bambolim, Goa. The strains were distributed amongst 23 different Salmonella serotypes. The commonest serotypes encountered were S.typhimurium (66%) and S.typhi (24%), the other serotypes were S.bareilly (5.4%), S.paratyphi B (1.2%), S.newport (1.2%) and S.chester (0.8%). Stool samples yielded the maximum Salmonella isolates of which the S.typhimurium was the highest followed by S.bareilly.

Clinico-microbiological study of dermatophytoses.

In the present series, 80 cases of dermatophytoses were subjected to mycological examination including microscopy and culture the mycological findings were correlated with clinical presentation of the patients. The isolation rate was 62.5 percent. Fungal culture was successful in 36.25 percent of cases, Trichophyton rubrum being the commonest etiological agent accounting for 55.18 percent of cases.