Biomedical subjects

Zafar Hussain

Publications and source records attributed to Zafar Hussain.

6 recordsLinked to original sources

PubMed2006

Prospective comparison of a new chromogenic medium, MRSASelect, to CHROMagar MRSA and mannitol-salt medium supplemented with oxacillin or cefoxitin for detection of methicillin-resistant Staphylococcus aureus.

MRSASelect agar was compared to CHROMagar, mannitol-salt agar with oxacillin, and mannitol-salt agar with cefoxitin (MSA-CFOX) for the isolation of methicillin-resistant Staphylococcus aureus (MRSA). The sensitivities and specificities were 97.3% and 99.8%, 82.9% and 99.1%, 80.2% and 79%, and 99.1% and 84.8%, respectively. MSA-CFOX and MRSASelect had a high sensitivity. MRSASelect, however, was more specific and proved to be a more reliable and rapid medium for the detection of MRSA.

Agar↗

PubMed2004

Performance of the TechLab C. DIFF CHEK-60 enzyme immunoassay (EIA) in combination with the C. difficile Tox A/B II EIA kit, the Triage C. difficile panel immunoassay, and a cytotoxin assay for diagnosis of Clostridium difficile-associated diarrhea.

We compared a recently marketed enzyme immunoassay for glutamate dehydrogenase (GDH), TechLab's C. DIFF CHEK-60 (TL-GDH), in combination with the C. difficile Tox A/B II enzyme immunoassay (Tox-A/B) with (i) the Triage C. difficile test, which detects both GDH (TR-GDH) and toxin A (TR-Tox-A); (ii) an in-house cytotoxin assay (C-Tox); and (iii) stool cultures for C. difficile. All C. difficile isolates were tested for the presence of the toxin genes by PCR. If a toxin gene-positive strain of Clostridium difficile was recovered and a toxin was detected by any method, the result was considered to be truly positive. Eighty-seven of 93 and 79 of 93 C. difficile culture-positive samples were also TL-GDH and TR-GDH positive, respectively. No test was able to detect toxin in all samples with true-positive results. Tox-A/B and TR-Tox-A in combination with the GDH detection tests and C-Tox were able to identify 52 and 50 samples with true-positive results. Tox-A/B and TR-Tox-A would have missed 15 and 31% of cases of C. difficile-associated diarrhea, respectively, if used alone.

Bacterial Proteins↗

PubMed2004

New quadriplex PCR assay for detection of methicillin and mupirocin resistance and simultaneous discrimination of Staphylococcus aureus from coagulase-negative staphylococci.

Major challenges in diagnostic molecular microbiology are to develop a simple assay to distinguish Staphylococcus aureus from the less virulent but clinically important coagulase-negative staphylococci (CoNS) and to simultaneously determine their antibiotic resistance profiles. Multiplex PCR assays have been developed for the detection of methicillin- and mupirocin-resistant S. aureus and CoNS but not for the simultaneous discrimination of S. aureus from CoNS. We designed a new set of Staphylococcus genus-specific primers and developed a novel quadriplex PCR assay targeting the 16S rRNA (Staphylococcus genus specific), nuc (S. aureus species specific), mecA (a determinant of methicillin resistance), and mupA (a determinant of mupirocin resistance) genes to identify most staphylococci, to discriminate S. aureus from CoNS and other bacteria, and to simultaneously detect methicillin and mupirocin resistance. Validation of the assay with 96 ATCC control strains and 323 previously characterized clinical isolates, including methicillin- and mupirocin-sensitive and -resistant S. aureus and CoNS isolates and other bacteria, demonstrated 100% sensitivity, specificity, and accuracy. This assay represents a simple, rapid, accurate, and reliable approach for the detection of methicillin- and mupirocin-resistant staphylococci and offers the hope of preventing their widespread dissemination through early and reliable detection.

Anti-Bacterial Agents↗

PubMed2003

Renal transplantation in developing countries.

Healthcare in developing countries less funded than developed nations (0.8 to 4% vs. 10 to 15%, respectively), and must contend against approximately 1/3 of the population living below the poverty line ($1US/day), poor literacy (58% males/29% females), and less access to potable water and basic sanitation. Cultural and societal constraints combine with these economic obstacles to translate into poor transplantation activity. Donor shortage is a universal problem. Paid donation comprises 50% of all transplants in Pakistan. Post-transplant infections are a major problem in developing countries, with 15% developing tuberculosis, 30% cytomegalovirus, and nearly 50% bacterial infections. The solutions to these problems may seem simplistic: alleviate poverty, educate the general population, and expand the transplant programs in public sector hospitals where commerce is less likely to play a major role. The SIUT model of funding in a community-government partnership has increased the number of transplantations and patient and organ survival substantially. Over the last 15 years, it has operated by complete financial transparency, public audit and accountability. The scheme has proven effective and currently 110 transplants/year are performed, with free after care and immunosuppressive drugs. Confidence has been built in the community, with strong donations of money, equipment and medicines. We believe this model could be sustained in other developing nations.

Developing Countries↗

PubMed2003

Clinical usefulness of components of the Triage immunoassay, enzyme immunoassay for toxins A and B, and cytotoxin B tissue culture assay for the diagnosis of Clostridium difficile diarrhea.

We studied 557 nonduplicate fresh stool specimens from adult patients clinically suspected of having Clostridium difficile-associated diarrhea. All samples were tested in parallel with an in-house cytotoxin B tissue culture assay (CTA), the C DIFFICILE TOX A/B II test (TA/B; TechLab, Blacksburg, VA), and the Triage Micro C DIFFICILE Panel (Biosite Diagnostics, San Diego, CA). The Triage device detects toxin A (TA) and glutamate dehydrogenase (GDH) simultaneously. Of the specimens, 350 were negative and 95 were positive for all markers. Another 112 specimens yielded discrepant results. The CTA found 143 positive specimens. Results of the components of the Triage and TA/B were compared separately with those of CTA. GDH was the most sensitive but least specific marker, whereas TA and TA/B were less sensitive but highly specific. Because of these attributes and a quick turnaround time, GDH would be the best screening test for C difficile-associated diarrhea. CTA detected the highest number of cases of C difficile-associated diarrhea and would be most useful as a confirmatory test for GDH-positive and TA-negative specimens.

Bacterial Proteins↗

PubMed2002

Detection of methicillin resistance in primary blood culture isolates of coagulase-negative staphylococci by PCR, slide agglutination, disk diffusion, and a commercial method.

The methicillin resistance of 363 coagulase-negative staphylococci isolated from blood cultures was determined by a slide latex agglutination (LA) test for penicillin-binding protein 2a (PBP 2a), the presence of the mecA gene by PCR, disk diffusion, and Vitek. LA was performed on primary cultures, and PBP 2a expression was induced by placing an oxacillin disk in the primary inoculum. Compared to the PCR results, LA was the most sensitive and specific in the detection of methicillin resistance. Without induction, LA failed to detect 50% of mecA-positive strains grown on two different media.

Bacteremia↗