Bactericidal activity of M protein conserved region antibodies against group A streptococcal isolates from the Northern Thai population.

BACKGROUND: Most group A streptococcal (GAS) vaccine strategies have focused on the surface M protein, a major virulence factor of GAS. The amino-terminus of the M protein elicits antibodies, that are both opsonic and protective, but which are type specific. J14, a chimeric peptide that contains 14 amino acids from the M protein conserved C-region at the carboxy-terminus, offers the possibility of a vaccine which will elicit protective opsonic antibodies against multiple different GAS strains. In this study, we searched for J14 and J14-like sequences and the number of their repeats in the C-region of the M protein from GAS strains isolated from the Northern Thai population. Then, we examined the bactericidal activity of J14, J14.1, J14-R1 and J14-R2 antisera against multiple Thai GAS strains. RESULTS: The emm genes of GAS isolates were sequenced and grouped as 14 different J14-types. The most diversity of J14-types was found in the C1-repeat. The J14.1 type was the major sequence in the C2 and C3-repeats. We have shown that antisera raised against the M protein conserved C-repeat region peptides, J14, J14.1, J14-R1 and J14-R2, commonly found in GAS isolates from the Northern Thai population, are able to kill GAS of multiple different emm types derived from an endemic area. The mean percent of bactericidal activities for all J14 and J14-like peptide antisera against GAS isolates were more than 70%. The mean percent of bactericidal activity was highest for J14 antisera followed by J14-R2, J14.1 and J14-R1 antisera. CONCLUSION: Our study demonstrated that antisera raised against the M protein conserved C-repeat region are able to kill multiple different strains of GAS isolated from the Northern Thai population. Therefore, the four conserved "J14" peptides have the potential to be used as GAS vaccine candidates to prevent streptococcal infections in an endemic area.

M protein typing of Thai group A streptococcal isolates by PCR-Restriction fragment length polymorphism analysis.

BACKGROUND: Group A streptococcal (GAS) infections can lead to the development of severe post-infectious sequelae, such as rheumatic fever (RF) and rheumatic heart disease (RHD). RF and RHD are a major health concern in developing countries, and in indigenous populations of developed nations. The majority of GAS isolates are M protein-nontypeable (MNT) by standard serotyping. However, GAS typing is a necessary tool in the epidemiologically analysis of GAS and provides useful information for vaccine development. Although DNA sequencing is the most conclusive method for M protein typing, this is not a feasible approach especially in developing countries. To overcome this problem, we have developed a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)-based assay for molecular typing the M protein gene (emm) of GAS. RESULTS: Using one pair of primers, 13 known GAS M types showed one to four bands of PCR products and after digestion with Alu I, they gave different RFLP patterns. Of 106 GAS isolates examined from the normal Thai population and from patients with GAS-associated complications including RHD, 95 isolates gave RFLP patterns that corresponded to the 13 known M types. Only 11 isolates gave RFLP patterns that differed from the 13 known M types. These were then analyzed by DNA sequencing and six additional M types were identified. In addition, we found that M93 GAS was the most common M type in the population studied, and is consistent with a previous study of Thai GAS isolates. CONCLUSION: PCR-RFLP analysis has the potential for the rapid screening of different GAS M types and is therefore considerably advantageous as an alternative M typing approach in developing countries in which GAS is endemic.

Entomophthoromycosis in Maharaj Nakorn Chiang Mai Hospital.

OBJECTIVE: To review documented entomophthoromycosis patients at Maharaj Nakorn Chiang Mai Hospital from 1985 to 2001. MATERIAL AND METHOD: A retrospective review was performed at Maharaj Nakorn Chiang Mai Hospital from 1985 to 2001. Eight cases of entomophthoromycosis were found between 1988 and 1993, with five patients diagnosed as subcutaneous zygomycosis, I GI entomophthoromycosis and 2 rhinofacial zygomycosis. RESULTS: The subcutaneous zygomycosis group was composed of 5 female patients, aged 7- 77 years. They presented with a painless subcutaneous mass, which was solitary or multiple and most commonly found on the extremities. The duration of disease was between 3 months to 5 years. The cultures grew Basidiobolus ranarum. A case of GI entomophthoromycosis was seen in a 34 year old man, who presented with dyspepsia, multiple intraabodminal masses and peritonitis. Two cases of conidiobolomycosis (rhinofacial zygomycosis) were seen. These two patients were male, 26 and 39 years old, and they presented with unilateral nasal obstruction from a mass at the inferior turbinate. The cultures grew Conidiobolus coronatus. CONCLUSION: Entomophthoromycosis in the northern part of Thailand is rare. The disease should be differentially diagnosed by a chronic painless tumor. The patients in this review responded very well to the recommended therapy.

Parvovirus B19 infection in children with acute illness and rash.

Parvovirus B19 is responsible for a variety of cutaneous diseases, including erythema infectiosum and papular purpuric gloves-and-socks syndrome. It is also associated with other dermatologic diseases, such as systemic lupus erythematosus. To study the prevalence of parvovirus B19 infection in children with acute illness and rash, we did a prospective study of 110 children at the Chiang Mai University teaching hospital from January 2001 to November 2003. Sera from these patients were analyzed for immunoglobulin M and immunoglobulin G antibodies against human parvovirus B19 using enzyme-linked immunosorbent assay techniques. From a total of 110 patients with acute illness and rash, there were paired serum samples for 90 patients and single serum sample for 20 patients. For those with paired serum samples, there were three patients with recent parvovirus B19 infection that presented with erythema infectiosum, urticaria, and lupus erythematosus, respectively. Immunoglobulin G antibodies were tested in serum samples of 103 children; 28.2% were positive. These data indicate that parvovirus B19 is not a common cause of acute illness and rash in children.

Scabies in Thai orphanages.

BACKGROUND: Scabies outbreaks have emerged in the orphanages in Chiang Mai, Thailand. Sulfur has been accepted as the standard treatment for childhood scabies in Thailand. Sulfur was administered in the mass treatment in two orphanages. The present study surveys the prevalence of scabies in these orphans the year following the mass treatment program. METHODS: The authors visited the two orphanages over the course of 1 year. Children at the orphanages were examined. Cases of scabies and their contacts were treated. RESULTS: The prevalence of scabies was 87.3% before the mass treatment, and 2 months after treatment the prevalence of scabies was reduced to a prevalence of <10%, which was maintained until the end of the present study (P < 0.01 for each visit). CONCLUSION: Sulfur is effective for treating scabies outbreaks where the cost of treatment is a major concern. In order to control the scabies outbreak and to prevent further outbreaks, the authors emphasize that an ongoing process of follow up after mass treatment is necessary.

Sulfur for scabies outbreaks in orphanages.

Scabies outbreaks occurred in two large orphanages in Chiang Mai, Thailand. Since we were concerned about the availability, safety, and cost of scabicides in Thailand, sulfur in petrolatum was our choice for mass treatment of the children. We studied the efficacy of sulfur in children 2 months to 6 years of age. After the treatment, 47% and 71% of the 102 patients were cured in 2 weeks and 4 weeks, respectively. Only three preschool children developed a mild facial irritation after the first application. This agent is a safe and cheap choice for mass therapy.

Entomophthoromycosis in Maharaj Nakorn Chiang Mai Hospital.

OBJECTIVE: To review documented entomophthoromycosis patients at Maharaj Nakorn Chiang Mai Hospital from 1985 to 2001. MATERIAL AND METHOD: A retrospective review was performed at Maharaj Nakorn Chiang Mai Hospital from 1985 to 2001. Eight cases of entomophthoromycosis were found between 1988 and 1993, with five patients diagnosed as subcutaneous zygomycosis, I GI entomophthoromycosis and 2 rhinofacial zygomycosis. RESULTS: The subcutaneous zygomycosis group was composed of 5 female patients, aged 7- 77 years. They presented with a painless subcutaneous mass, which was solitary or multiple and most commonly found on the extremities. The duration of disease was between 3 months to 5 years. The cultures grew Basidiobolus ranarum. A case of GI entomophthoromycosis was seen in a 34 year old man, who presented with dyspepsia, multiple intraabodminal masses and peritonitis. Two cases of conidiobolomycosis (rhinofacial zygomycosis) were seen. These two patients were male, 26 and 39 years old, and they presented with unilateral nasal obstruction from a mass at the inferior turbinate. The cultures grew Conidiobolus coronatus. CONCLUSION: Entomophthoromycosis in the northern part of Thailand is rare. The disease should be differentially diagnosed by a chronic painless tumor. The patients in this review responded very well to the recommended therapy.