This investigation was initiated as a consequence of several cases of diarrhea in a nursery ward for preterm babies in Nairobi, Kenya. Ten lactose-positive colonies were isolated from the stools of each of 30 neonates, regardless of whether they had diarrhea; 229 strains were identified as Escherichia coli and 65 strains were identified as Klebsiella pneumoniae. Six strains were lost during laboratory handling. No other bacterial, viral, or parasitic enteropathogens were identified. Using synthetic alkaline phosphatase-labeled probes, the bacterial isolates were found to be negative for the presence of genes coding for heat-stable and heat-labile enterotoxins. Seventy-eight E. coli strains isolated from a total of 13 neonates possessed the E. coli enteropathogenic adhesion factor (EAF) gene, as demonstrated by the use of a cloned radiolabeled DNA fragment probe. These strains possessed similar plasmid profiles constituting a core plasmid profile, and while all adhered to HeLa cells, none produced Vero cell cytotoxins. The EAF gene was located on a 65-megadalton plasmid. Serotyping showed the strains to be of serogroup 0111 and serotype H nontypable, a well known enteropathogenic type. Five neonates died during the outbreak, and the fatality rate was 30.7% (4 of 13) for neonates infected with EAF-positive E. coli strains compared with 7.7% (1 of 13) for neonates from whom only EAF-negative E. coli strains were isolated. K. pneumoniae only was isolated from five neonates.

M. & Olsvik, 0. Antimicrobial resistance of enteropathogenic Escherichia coli strains from a nosocomial outbreak in Kenya. APMIS 99: 728-734, 1991.The majority of the 78 enteropathogenic (EPEC) and the 151 non-EPEC Escherichia coli strains isolated from preterm neonates during an outbreak of gastroenteritis in a hospital in Nairobi, Kenya, were resistant to trimethoprim-sulfamethoxaxole, chloramphenicol, oxytetracycline and ampicillin, but only a few strains were resistant to cefazolin, cefamandole, cefotaxime, amikacin and nalidixic acid. Fourteen different antimicrobial resistance patterns were observed in the 229 strains of E. coli analysed. Eighty-two percent of the EPEC strains belonged to two resistance patterns compared with 79% of non-EPEC strains which exhibited three resistance patterns. There was no consistent relationship between plasmid profile group and antimicrobial resistance pattern, although one resistance pattern was more frequently observed in EAF-positive strains belonging to the dominant plasmid profile group. Nine percent of the EPEC strains were resistant to gentamicin compared to 37% in the non-EPEC group. No correlation was observed between administration of gentamicin and percentage of resistant strains isolated. None of the nine neonates receiving gentamicin died during the outbreak. Gentamicin resistance was observed in E. coli strains from six out of these nine neonates. Five out of fourteen neonates who received other antimicrobials, or no antibiotic treatment at all, died.Enteropathogenic Escherichia coli (EPEC) was the first E. coli t o be identified as a major cause of diarrheal disease (1 2). Recent reports indicate EPEC to be the first o r second most important bacterial cause of infantile diarrhea in some developing countries (1,5), and a cause of sporadic outbreaks of diarrhea in the developed countries (12,19,22). Although serogrouping and serotyping have remained the standard reference ~ ~

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Stool samples were examined from 30 preterm neonates admitted to a nursery ward; 16 neonates had diarrhea, 12 constituted an age-matched control group without diarrhea, and 2 had an unknown history regarding diarrhea. Variable numbers of enteropathogenic Escherichia coli serotype 0111:HNT strains possessing the gene coding for the enteroadherence factor (EAF) were found in stool samples from 13 of the neonates. No other microbiological enteropathogen was found. A total of 294 strains (9 or 10 from each neonate, comprising 229 E. coli and 65 Klebsielka pneumoniae strains) were characterized with respect to plasmid content and grouped into 37 plasmid profile groups. Diarrhea was found not to be correlated with any specific plasmid profile or with the presence of the EAF-positive strains but rather with the number of strains with one specific plasmid profile or with the number of EAF-positive strains (of the 9 or 10 strains) isolated from each stool sample. AU the neonates who died had diarrhea (5 died of 16 with diarrhea); all five of the neonates who died possessed strains with one specific plasmid profile group, and EAF-positive strains were isolated from four of them. Of the seven neonates from whom seven or more EAF-positive isolates were isolated, three died, compared with only one of five of those from whom only a few (1 to 3 of 10) EAF-positive strains were isolated. Both plasmid profiling and genetic probing with the EAF probe were found to be good alternatives when serotyping is not available for identification of 0111:HNT enteropathogenic E. coli strains.

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