No abstract

No abstract

SYNOPSIS Pseudomonas putrefaciens, a strongly H2S-producing pseudomonad, was isolated from 10 human infections over a two-year period. In one patient the organism was repeatedly isolated from a phlegmone developing in the depth of a varicose leg ulcer. This is the first report on the occurrence of Ps. putrefaciens in humans outside the USA and the first to provide the detailed account of a clinical observation where the opportunistic pathogenic role of this unfamiliar organism has been sufficiently documented.Data are presented on the bacteriological properties and on the antibiotic sensitivity of Ps.putrefaciens.Although Pseudomonas aeruginosa is by far the most common pathogenic species of the genus Pseudomonas, several other species have recently attracted the attention of the clinical bacteriologist. Recognition of these species has long been hampered by the lack of a clear classification system for nonfermentative Gram-negative bacteria and by the considerable confusion in their nomenclature. Improvements in bacteriological methods and the increased incidence of opportunistic and nosocomial infections have stimulated interest in Pseudomonas species other than Ps. aeruginosa. Simple criteria for characterization of unusual Pseudomonas species have been presented in a series of well-documented papers (Gilardi, 1971(Gilardi, , 1972Von Graevenitz, 1973).Although easy to recognize because of its abundant hydrogen sulphide production, Ps. putrefaciens is one of the least well-known pseudomonads in medical bacteriology, and we have seen no mention of the isolation of this species in the European literature.The first human isolates of a nonfermenting, H2S-producing Gram-negative rod with polar flagellation were described by King in 1964, who gave them the provisional label 'lb'. In 1970, von Graevenitz and Simon reported 13 isolations of the same microorganism from different clinical speciRequests for reprints should be addressed to Professor J.

A new enrichment medium for the recovery of pathogenic Yersinia enterocolitica serogroup 0:3 from naturally infected meat products based on three selective agents, Irgasan, ticarcihlin, and potassium chlorate (ITC), was compared with several other one-or two-step enrichments. Y. enterocolitica serogroup 0:3 was recovered from 96.5% of 29 pork tongues, 24% of 50 ground pork samples, 16% of 25 masseter muscle samples, and 61% of tonsils. ITC was by far the most sensitive method for the recovery of Y. enterocolitica 0:3, especially from ground meat and masseter muscles, while cold and two-step enrichments yielded better results for nonpathogenic strains. Plating of ITC enrichments onto SS-deoxycholate-calcium agar gave overall better results than plating onto cefsulodin-Irgasan-novobiocin agar for serogroup 0:3.

The intestinal contents of 59 Zairese freshwater fish were examined for the presence of potential human enteric pathogens. Edwardsiella tarda and Plesiomonas shigelloides were isolated from 57 and 59% of them, respectively. For both microorganisms there was a significant difference between the isolation rates from lake and river fish: whereas E. tarda was much more frequently isolated from lake fish than was P. shigelloides, the reverse was observed for river fish. The authors hypothesize that sporadic cases of tropical diarrhea with E. tarda or P. shigelloides can be traced to contact with or consumption of freshwater fish.

All of 37 recent human isolates of Edwardsiella tarda were resistant to colistin. All strains were resistant to 6.3 μg of sodium colistimethate per ml; 82% of them were resistant to 100 μg/ml. With 34 Salmonella strains, the average minimal inhibitory concentration (MIC) was 1.6 μg of sodium colistimethate per ml. There was virtually no overlapping of MIC values between both groups of bacteria. Using the Kirby-Bauer method and 10-μg colistin disks, inhibition zone diameters were less than 11 mm for all Edwardsiella strains, and larger for all Salmonella strains. An atypical, mannitol-fermenting strain of E. tarda was resistant to colistin. It is concluded that E. tarda is naturally resistant to colistin, that this property may be helpful in differentiation, and that colistin should be tried in enrichment and selective media for the isolation of E. tarda . It was also observed that, under conditions as described, all strains of E. tarda were susceptible to streptomycin and to novobiocin, whereas all strains of Salmonella were resistant.

No abstract

In 2,861 consecutive patients undergoing appendicectomy for clinically suspected appendicitis an enteric pathogen was isolated from the appendix in almost 7% using an optimal combination of culture media. The pathogenic Yersinia enterocolitica serotypes 03 and 09 predominated (3.6%), followed by Campylobacter and nontyphoid Salmonella. The same pathogen was isolated from the stool in 72.5% of patients with a culture-positive appendix and in 84.1% of those positive for a pathogenic Yersinia. Conversely, no pathogenic Yersinia were isolated in 326 gynaecologic control patients, in whom a normal appendix was removed. No frank appendicitis but mesenteric adenitis and/or terminal ileitis were found in 62.3% of 138 patients with a culture positive appendix, and in 74.6% of those positive for a pathogenic Yersinia. Histologic findings available in 135 patients showed acute suppurative appendicitis in only six (4.5%) patients, and in only one of 73 (1.4%) positive for a pathogenic Yersinia. In contrast, 46.8% of a group of 345 culture-negative appendices showed acute inflammation. A positive stool culture in a patient with suspected appendicitis, if consistent with sonographic and clinical findings, should be taken as strong evidence against the presence of true appendicitis.