Two hundred strains of Klebsiella species isolated from clinical specimens over a four-month period were biotyped as Klebsiella aerogenes (173 strains), Klebsiella ozaenae (15 strains), Klebsiella edwardsii (5 strains), Klebsiella atlantae (2 strains) and Klebsiella oxytoca (1 strain). Klebsiella aerogenes and Klebsiella ozaenae were more resistant towards antibiotics when compared with other species. Colonial morphology on eosin methylene blue agar (Oxoid) was not found useful for differentiations of Klebsiella biotypes.
Six independent isolates of Klebsiella from hospital environmental sources in Malaysia were found to be resistant to at least ampicillin, carbenicillin, cefoperazone, chloramphenicol, gentamicin and tetracycline. On the basis of their antibiograms, they were divided into four antibiogroups. They transferred all or part of their multiple antibiotic resistance traits to E. coli by conjugation. The results suggest that these Klebsiella strains harbour self-transmissible R plasmids. The significance of these findings are discussed.
A clinical isolate of Salmonella typhi (Vi phage type 25), resistant to chloramphenicol, streptomycin and tetracycline, was examined for the presence of R plasmids. Results from conjugation, agarose gel electrophoresis and transformation experiments indicated that it harboured a single large self-transmissible R plasmid which coded for both the chloramphenicol and tetracycline resistance traits.
Cultures of Staphylococcus aureus from eight food poisoning incidents in Malaysia were examined for their ability to produce enterotoxins. Five of the eight strains were found to be enterotoxigenic, the enterotoxins detected being A and E (three strains), A and C (one strain), and C (one strain). Penicillinase production was observed in four of the five enterotoxigenic strains; the penicillin·sensitive strain was also found to be coagulase-negative. The bacteriological and epidemiological investigations for confirming staphylococcal food poisoning are presented. The preventive measures to be taken in reducing such outbreaks are emphasized.
The current drugs recommended for treatment of melioidosis are tetracycline, chloramphenicol and cotrimoxazole. Unfortunately these drugs are not the drug of choice in an acutely ill patient with septicaemia prior to the availability of laboratory results. With the discovery of the new cephalosporins which have a broad spectrum of activity clinicians are using them either alone or in combination with other antibiotics in such critical situations. Hence, an in-vitro study was carried out on the susceptibility of 41 strains of P. pseudomallei isolated in Malaysia, to these new cephalosporins and a new quinolone. The results showed that all the cephalosporins tested had some activity on the strains tested, with ceftazidime being the most active drug. Pefloxacin had very poor activity. However, further clinical studies are required to determine the duration, dosage and in-vivo activity of the antibiotics.
Plesiomonas shigelloides was isolated from 5 (2.1%) of the 234 children with diarrhoea and none of the 230 controls. In one child, the organism was found in association with Salmonella. Two strains had Shigella sonnei phase I antigen. All the strains were susceptible to the aminoglycosides, cephalosporins, nalidixic acid, nitrofurantoin, chloramphenicol and cotrimoxazole; but resistant to the penicillins. Alkaline peptone water enrichment subcultured to desoxycholale citrate agar proved to be a useful method for isolating this organism from faeces. As the roie of P. shigelloides in causing gastrointestinal disease remains controversial, further studies are necessary to determine its enteropathogenicily.
Antibiotic resistance in Gram-negative bacteria, particularly Salmonella and Shigella, requires surveillance worldwide. This study describes results of surveys in Hong Kong, Bangkok and Kuala Lumpur. All strains were isolated in hospitals which have large community catchment areas in addition to specialised hospital units. The prevalence of resistant strains was high in all areas. Gram-negative bacteria such as Enterobacter associated with hospital infections were resistant to penicillins and cephalosporins, with gentamicin resistance ranging from about 20% in Kuala Lumpur and Hong Kong, to 35% in Bangkok. Ninety-seven percent of Shigella isolated in Thailand were resistant to ampicillin. About 10% of Salmonella were resistant to chloramphenicol in all three centres.
Tatumella ptyseos, the type species for the genus Tatumella, is a newly established member of the Family Enterobacteriaceae. It is a Gram-negative, oxidase negative, fermentative rod that grows on Mac Conkey agar. This first isolate was obtained from the blood culture of a neonate having neonatal jaundice with presumed sepsis. The organism was in vitro sensitive to Gentamicin, Chloramphenicol, Cotrimoxazole and Ampicillin. The patient was treated with Ampicillin and Gentamicin and recovered uneventfully.
The in vitro activity of teicoplanin and A16686, two new glycopeptide antibiotics was determined against 196 isolates of anaerobic bacteria. The activity of teicoplanin and A16686, in comparison with that of vancomycin, clindamycin, erythromycin and fusidic acid was 2 to 16 times higher against the gram positive anaerobes, namely, Propionibacterium acnes, Clostridium perfringens, Clostridium difficile, Clostridium species, Peptococcus species and Peptostreptococcus species. However, Bacteroides fragilis was resistant to teicoplanin and A16686 while Bacteroides melaninogenicus and Bacteroides bivius were found to be sensitive.
The in-vitro activity of cefotaxime and cefoperazone were compared using clinically isolated Escherichia coli, Klebsiella spp and Pseudomonas aeruginosa. Cefotaxime was found on a weight to weight basis, to be much more active than cefoperazone. All the three species studied show the presence of cefoperazone-resistant population which were sensitive to cefotaxime. The possible mechanisms of resistance to these antibiotics were discussed.
Six Campylobacter jejuni clinical isolates were examined for the occurrence of plasmids in association with antibiotic resistances as well as conjugal transfer. All the isolates were found to carry three similar plasmids of 78 kb, 12.6 kb and 3.3 kb in size. Multiple resistance to at least three of the antibiotics tested was observed with resistance to tetracycline most common. En bloc transfer of donor resistances at frequencies ranging from 10(-8) to 10(-4) were seen in all but one of the isolates during conjugation. The conjugal transfer of erythromycin, neomycin and streptomycin were observed to occur at frequencies similar to that of chloramphenicol, kanamycin and tetracycline. In isolate ABA94, three different antibiotic resistance phenotypes of the transconjugants were seen. In addition to en bloc transfer of the donor resistances, in approximately 10% of the transconjugants the streptomycin resistance was lost although these transconjugants carried the donor complement of three plasmids. In a further 1% of the transconjugants, resistance to kanamycin only was detected and these transconjugants did not carry any plasmids.
Methicillin-resistant Staphylococcus aureus (MRSA) as a hospital pathogen has presented many clinical problems in the University Hospital, Kuala Lumpur, Malaysia since 1978. The need for control of spread of these organisms became evident by 1985 when it was noted that the incidence of MRSA among S. aureus isolated from hospital inpatients had increased from 11.5% in 1979 to 18.8% in 1985. The characteristics of 50 MRSA isolates associated with nosocomial infections in the hospital are described here. The predominant strains produced Type IV coagulase and 84% of isolates studied showed moderate to high resistance to methicillin with MIC values of 25 mg l-1 or higher. All the MRSA isolates that could be phagetyped were susceptible to Group III phages, with 76.6% of the isolates being susceptible to phage 85. At least 10 different patterns were distinguishable by plasmid typing, the majority of isolates harbouring up to four small plasmids.