PubMed Health⌕ Search

Biomedical subjects

Johnson Lin

Publications and source records attributed to Johnson Lin.

13 recordsLinked to original sources
PubMed2006

Antimicrobial susceptibility patterns and characterization of clinical isolates of Staphylococcus aureus in KwaZulu-Natal province, South Africa.

BACKGROUND: Antimicrobial resistance of Staphylococcus aureus especially methicillin-resistant S. aureus (MRSA) continues to be a problem for clinicians worldwide. However, few data on the antibiotic susceptibility patterns of S. aureus isolates in South Africa have been reported and the prevalence of MRSA in the KwaZulu-Natal (KZN) province is unknown. In addition, information on the characterization of S. aureus in this province is unavailable. This study investigated the susceptibility pattern of 227 S. aureus isolates from the KZN province, South Africa. In addition, characterization of methicillin-sensitive S. aureus (MSSA) and MRSA are reported in this survey. METHODS: The in-vitro activities of 20 antibiotics against 227 consecutive non-duplicate S. aureus isolates from clinical samples in KZN province, South Africa were determined by the disk-diffusion technique. Isolates resistant to oxacillin and mupirocin were confirmed by PCR detection of the mecA and mup genes respectively. PCR-RFLP of the coagulase gene was employed in the characterization of MSSA and MRSA. RESULTS: All the isolates were susceptible to vancomycin, teicoplanin and fusidic acid, and 26.9% of isolates studied were confirmed as MRSA. More than 80% of MRSA were resistant to at least four classes of antibiotics and isolates grouped in antibiotype 8 appears to be widespread in the province. The MSSA were also susceptible to streptomycin, neomycin and minocycline, while less than 1% was resistant to chloramphenicol, ciprofloxacin, rifampicin and mupirocin. The inducible MLSB phenotype was detected in 10.8% of MSSA and 82% of MRSA respectively, and one MSSA and one MRSA exhibited high-level resistance to mupirocin. There was good correlation between antibiotyping and PCR-RFLP of the coagulase gene in the characterization of MRSA in antibiotypes 1, 5 and 12. CONCLUSION: In view of the high resistance rates of MRSA to gentamicin, erythromycin, clindamycin, rifampicin and trimethoprim, treatment of MRSA infections in this province with these antibacterial agents would be unreliable. There is an emerging trend of mupirocin resistance among S. aureus isolates in the province. PCR-RFLP of the coagulase gene was able to distinguish MSSA from MRSA and offers an attractive option to be considered in the rapid epidemiological analysis of S. aureus in South Africa. Continuous surveillance on resistance patterns and characterization of S. aureus in understanding new and emerging trends in South Africa is of utmost importance.

Anti-Bacterial Agents↗
PubMed2006

Molecular identification and characterization of mannitol-negative methicillin-resistant Staphylococcus aureus.

We report on the isolation, molecular identification, and characterization of 5 mannitol-negative methicillin-resistant Staphylococcus aureus (MRSA) from clinical samples in KwaZulu-Natal (KZN) province, South Africa. Identification based on phenotypic testing and polymerase chain reaction detection of the S. aureus species-specific nuc gene and the coagulase gene indicated that the mannitol-negative isolates were S. aureus. Furthermore, they were mecA positive, and SCCmec typing demonstrated that all the isolates harbored type IV SCCmec. API STAPH (Biomerieux, Marcy-l'Etoile, France) misidentified 2 mannitol-negative MRSA that belonged to the major clone in KZN province, as Staphylococcus lugdunensis. Although the prevalence and mechanism of mannitol-negative MRSA is unknown, laboratories are encouraged to investigate S. aureus with atypical characteristics.

Bacterial Proteins↗
PubMed2006

Renal cell carcinoma producing granulocyte colony-stimulating factor.

Severe neutrophilia caused by renal cell carcinoma secreting granulocyte colony-stimulating factor (G-CSF) is a rare manifestation of renal cancer. A 70-year-old woman presented with a 2-year history of severe anemia, severe neutrophilia and elevated serum G-CSF, which completely resolved after radical nephrectomy. Histologic study revealed a histologically high-grade, stage pT1N0M0 renal cell carcinoma. Serum G-CSF level was elevated preoperatively and returned to normal postoperatively. Immunohistochemical study of the tumor tissue using anti-G-CSF monoclonal antibody revealed positive staining in the cancer cells. Careful follow-up of white blood cell count and physical examination for neck lymph node enlargement led to the timely identification of tumor recurrence 17 months after surgery, which resulted in prompt and successful salvage immunotherapy. In this case, G-CSF appeared to contribute to the leukocytosis, as both serum G-CSF level and white blood cell count closely correlated with the clinical tumor growth. White blood cell count should be closely monitored as an indicator of disease activity in patients with G-CSF-producing renal cell carcinoma.

Aged↗
PubMed2006

Clinical outcome of primary gastric lymphoma treated with chemotherapy alone or surgery followed by chemotherapy.

BACKGROUND: The role of surgical resection in the treatment of primary gastric lymphoma (PGL) remains unclear. This retrospective study evaluated the clinical outcome of PGL treated with chemotherapy alone or surgery followed by chemotherapy. METHODS: During 1986-2003, 59 patients with PGL (other than mucosa-associated lymphoid tissue type lymphoma) were identified from hospital files. The medical records, pathologic sections, radiographic images and treatment modalities of these patients were reviewed. Patients were categorized into localized (stage IE and IIE-1) and advanced (stage IIE-2 or beyond) stage groups. Survival was estimated by the Kaplan-Meier method. RESULTS: The study included 55 patients who received treatment at the same institute. Among them, 32 had localized PGL (15 stage IE, 17 stage IIE-1) and 23 had advanced disease. The median survival of the localized stage group was not reached during a mean follow-up of 168.1 +/- 16.7 months (95% confidence interval [CI], 135.4-200.8 months), while that of the advanced stage group was 33.0 +/- 6.8 months (95% CI, 19.7-46.5; p < 0.001, log-rank test). Among patients with localized PGL, the 5-year overall survival rate of those receiving chemotherapy alone (n = 19) or combination therapy (surgery followed by chemotherapy, n = 13) was 73.4% and 87.5%, respectively (p = 0.229). The 5-year disease-free survival was 68.4% and 84.6%, respectively (p = 0.540). However, post-chemotherapy life-threatening hemorrhage occurred in five of the 32 patients (15.6%) in the localized stage group: four in the chemotherapy-alone group, and one in the combination therapy group, all of whom had failed to achieve complete response. CONCLUSION: The clinical outcome of localized PGL treated by chemotherapy alone is similar to that treated by surgery followed by chemotherapy in terms of tumor response, disease-free survival and overall survival, suggesting that surgery be reserved for those with residual tumors after chemotherapy.

Adult↗
PubMed2006

Identification and molecular characterization of mannitol salt positive, coagulase-negative staphylococci from nasal samples of medical personnel and students.

The identification of mannitol salt positive, coagulase-negative staphylococci (CNS) is often disregarded when Staphylococcus aureus is screened in clinical samples using mannitol salt agar. However, the emergence of CNS as important human pathogens has indicated that reliable methods for the identification of clinically significant CNS are of great importance in understanding the epidemiology of infections caused by them. The identification and molecular characterization of mannitol salt positive CNS from nasal samples of medical personnel and students is reported here. A total of 84 mannitol salt positive staphylococcal isolates were obtained from 240 nasal samples, of which 15 were CNS. The API STAPH system classified the CNS isolates into six species, and one-third of the isolates were identified with confidence levels of <80 %. 16S-23S rRNA intergenic spacer length polymorphism analysis (ITS-PCR) identified only two species (Staphylococcus haemolyticus and Staphylococcus saprophyticus). This identification was confirmed by antibiotyping, species-specific PCR and PFGE. The results from this study indicate that ITS-PCR is a potentially useful and reliable tool, enabling hospital laboratories to obtain rapid, full and accurate identification of CNS at the species level.

Bacterial Typing Techniques↗
PubMed2005

Combination of cyclooxygenase-2 inhibitors and oxaliplatin increases the growth inhibition and death in human colon cancer cells.

The cyclooxygenase-2 (COX-2) protein is highly expressed in a variety of human cancers and has been reported to promote tumor growth. Non-steroidal anti-inflammatory drugs such as etodolac and celecoxib have been shown to inhibit COX-2 activity and may play a role in the chemoprevention of cancer. Oxaliplatin is a third-generation platinum compound that exhibits a different spectrum of activity compared with cisplatin. Other cisplatin-resistant tumors can still respond to oxaliplatin. However, the anticancer ability of the combination of COX-2 inhibitors and oxaliplatin is still unknown. In this study, we investigated the effects of combination of COX-2 inhibitors and oxaliplatin on the cell growth and survival in human colon cancer cells. Treatments with etodolac (0.3-0.5 mM) or celecoxib (20-80 microM) for 24 h concentration-dependently induced the cytotoxicity in the RKO colon carcinoma cells. Etodolac and celecoxib did not alter the COX-2 protein levels but inhibited its enzyme activity to reduce prostaglandin E2 production. Furthermore, the cell survival was concentration-dependently decreased following oxaliplatin (1-100 microM, 24 h) treatment. Combination of oxaliplatin and etodolac additively increased the death and growth inhibition of RKO cells. Survivin, an inhibitor protein of apoptosis, mediates anti-apoptosis and promotes cell division in cancer cells. Oxaliplatin or COX-2 inhibitors significantly decreased the levels of survivin proteins. Moreover, survivin proteins were markedly diminished following co-treatment with oxaliplatin and etodolac. Together, this is the first report that combination of COX-2 inhibitors and oxaliplatin can increase the reduction of survivin protein expression, growth inhibition, and death in human colon cancer cells.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Primary carcinoid tumor of prostate presenting with bone marrow metastases.

Primary carcinoid tumor of the prostate is a rare tumor derived from the amine precursor uptake and decarboxylation cells of the prostate. We report a case of a 71-year-old man who presented with progressive anemia due to bone marrow metastases from primary carcinoid tumor of the prostate. No other metastasis was found clinically. This pattern of metastasis is very unusual and illustrates that carcinoid tumor of the prostate may metastasize distantly without locoregional lymph node involvement. This unique case highlights the need for a multidisciplinary approach to the evaluation of a metastatic carcinoid tumor of an unknown primary and that it should include the prostate.

Aged↗
PubMed2005

The discovery of a multi-resistant Staphylococcus haemolyticus clone in the hospital and community environment in south western Nigeria.

Among clinically significant isolates of coagulase negative staphylococci, Staphylococcus haemolyticus is ranked second after Staphylococcus epidermidis. It has been associated with septicemia in newborns and various infections in persons with compromised host defenses and implanted foreign bodies. The existence of a multi-resistant Staphylococcus haemolyticus clone was discovered during a study on patients with skin and soft tissue infections at two local health clinics and in a referral hospital in South Western Nigeria. The clonal nature of these strains was determined by antibiotic susceptibility profile and pulsed field gel electrophoresis. This represents the first report of what appears to be a hospital-acquired and transmitted Staphylococcus haemolyticus clone in South Western Nigeria. Careful infection control measures and strain typing are urgently needed to understand species epidemiology and to limit the spread of multi-resistant strains within and beyond healthcare facilities.

Academic Medical Centers↗
PubMed2004

Hypersensitivity reactions to oxaliplatin: a case report and the success of a continuous infusional desensitization schedule.

Oxaliplatin is a third-generation platinum analog that is used mainly to treat advanced colorectal cancer. The reported incidence of hypersensitivity reactions to oxaliplatin, especially after multiple cycles of therapy, is less than 1%. We report a patient with metastatic colon cancer who developed a hypersensitivity reaction to oxaliplatin during the sixth cycle of combination chemotherapy with oxaliplatin, high-dose 5-fluorouracil and leucovorin. The same reaction occurred again after re-exposure to oxaliplatin 2 weeks later even with prophylactic administration of steroids and H1 antihistamines. After failing third-line treatment with oral tegafur-uracil, we desensitized the patient by using a fixed-rate 24-h continuous infusion of dilute oxaliplatin (0.15 mg/ml), in addition to steroids and H1 antihistamines. He had no hypersensitivity reaction during or after that infusion or when the same concentration was infused in the same way 2 weeks later. Because his condition subsequently deteriorated and the cancer progressed, no further oxaliplatin was given. Our experience does demonstrate, however, that a fixed-rate 24-h continuous infusion of oxaliplatin in a low concentration may prevent a hypersensitivity reaction in a previously sensitized patient.

Administration, Oral↗
PubMed2004

Isolation and molecular characterization of multiresistant Staphylococcus sciuri and Staphylococcus haemolyticus associated with skin and soft-tissue infections.

The isolation, molecular identification and genotyping of multiresistant Staphylococcus sciuri and Staphylococcus haemolyticus from skin and soft-tissue infections are reported. Accurate and full identification of three coagulase-negative staphylococcal isolates was achieved using PCR, while the API STAPH method failed to identify an isolate of S. haemolyticus fully. The PCR assay, which detects polymorphism in the 16S-23S rRNA spacer region, is shown to be potentially useful for rapid and accurate identification of coagulase-negative staphylococci. Identical PFGE type and antibiotic-resistance profiles of two methicillin-resistant S. haemolyticus isolates in this study suggest the existence of a multiresistant community clone.

Adult↗
PubMed2002

African traditional healers: what health care professionals need to know.

Traditional healing has always been a component of health care. In South Africa, traditional healers can obtain licences to practise but very little groundwork has been done to integrate Westernized medicine with traditional healing. The actual contribution of traditional healers to health care in the province of Kwa-Zulu Natal or South Africa is not known. This study determined the role of traditional healers in Durban, Kwa-Zulu Natal, the number of patients who consulted traditional healers, the types of conditions treated and the frequency of consultations. The opinions about physiotherapy of the patients who frequently consult traditional healers were also explored. Data were collected from 30 traditional healers and their 300 patients by means of questionnaires and interviews. The results show 70% of the patients would consult traditional healers as a first choice. Sangomas were the most popular type of healers and had as many as 20 patients per day. A significantly large number of patients consulted traditional healers for potentially life-threatening conditions. The patients knew very little or nothing about physiotherapy. We conclude that traditional healing is an integral component of health care in South Africa. Health care professionals need to be proactive in integrating traditional healing with Westernized practices to promote health for all.

Adult↗