Detection of inducible clindamycin resistance in staphylococci by disk diffusion induction test.

OBJECTIVE: To detect inducible clindamycin (CL) resistance in staphylococci by disk diffusion induction test (D-test). MATERIAL AND METHOD: One thousand one hundred eighty clinical isolates of staphylococci were tested for inducible CL resistance by placing erythromycin (E) disk and clindamycin disk 12 mm apart (edge to edge) on Mueller-Hinton agar plate inoculated with staphylococci. The flattening of CL zone (D-shaped zone) near E disk indicated an inducible CL resistance was observed after 18-24 h of incubation. RESULTS: Inducible CL resistance was detected in 9.9% of staphylococci isolates. It was found in methicillin-resistant Staphylococcus aureus (MRSA) more than methicillin-sensitive Staphylococcus aureus (MSSA) and coagulase-negative staphylococci (CoNS) 35.9%, 4.7%, and 5.5%, respectively. CONCLUSION: To avoid misinterpretation of CL result, D-test is recommended for routine detecting of inducible CL resistance in staphylococci. It provides the confident laboratory report of CL as resistant (D-shaped zone positive) or as susceptible (D-shaped zone negative) particular for E resistant isolates.

Examination of diarrheal stools in Hat Yai City, South Thailand, for Escherichia coli O157 and other diarrheagenic Escherichia coli using immunomagnetic separation and PCR method.

A total of 493 stool samples from diarrheal patients in Songklanagarind Hospital, in southern Thailand, were examined for Escherichia coli O157 by the culture method combined with an immunomagnetic separation (IMS) technique. E. coli O157 was not found, although the IMS-based method could detect 10(2)-10(3) CFU of artificially inoculated O157/g of stool samples. Polymerase chain reaction was also used for the detection and identification of diarrheagenic E coli from 530 stool samples. The target genes were eae for enteropathogenic E. coli (EPEC), stx for enterohemorrhagic E. coli (EHEC), elt and est for enterotoxigenic E. coli (ETEC), ipaH for enteroinvasive E. coli (EIEC), and aggR for enteroaggregative E. coli (EAggEC). Fifty-eight diarrheagenic E. coli strains were detected in 55 stool samples (10%) from 32 children and 23 adults. These included 31 EAggEC strains (5.8%), 13 ETEC strains (2.5%), 13 EPEC strains (2.5%), and one EIEC strain (0.2%). EHEC was not detected. The diarrheagenic E. coli strains were found mainly in children under 2 years of age (24 of 32 children). EAggEC strains and ETEC strains were susceptible to several antibiotics whereas the EPEC strains exhibited resistance to these antibiotics.

Clinical and epidemiological analyses of human pythiosis in Thailand.

BACKGROUND: Pythiosis is an emerging and life-threatening infectious disease in humans and animals that is caused by the pathogenic oomycete Pythium insidiosum. Human pythiosis is found mostly in Thailand, although disease in animals has been increasingly reported worldwide. Clinical information on human pythiosis is limited, and health care professionals are unfamiliar with the disease, leading to underdiagnosis, delayed treatment, and poor prognosis. METHODS: To retrospectively study the clinical and epidemiological features of human pythiosis, we analyzed clinical data from patients with pythiosis diagnosed during the period of January 1985 through June 2003 at 9 tertiary care hospitals throughout Thailand. RESULTS: A total of 102 cases of human pythiosis were documented nationwide. A substantial proportion (40%) of cases occurred in the last 4 years of the 18-year study interval. Clinical presentations fell into 4 groups: cutaneous/subcutaneous cases (5% of cases), vascular cases (59%), ocular cases (33%), and disseminated cases (3%). Almost all patients with cutaneous/subcutaneous, vascular, and disseminated pythiosis (85%) had underlying thalassemia-hemoglobinopathy syndrome. Most ocular cases (84%) were associated with no underlying disease. A majority of the patients were male (71%), were aged 20-60 years (86%), and reported an agricultural occupation (75%). Regarding treatment outcomes, all patients with disseminated infection died; 78% of patients with vascular disease required limb amputation, and 40% of these patients died; and 79% of patients with ocular pythiosis required enucleation/evisceration. CONCLUSIONS: Here, we report, to our knowledge, the largest case study of human pythiosis. The disease has high rates of morbidity and mortality. Early diagnosis and effective treatment are urgently needed to improve clinical outcomes. Because P. insidiosum is distributed worldwide and can infect healthy individuals, an awareness of human pythiosis should be promoted in Thailand and in other countries.