Biotypes of Klebsiella pneumoniae (sensu lato) and Enterobacter aerogenes characterised by differential substrate metabolism: application of the technique.

Abstract

SUMMARY A biochemical typing method is described for Klebsiella pneumoniae (sensu lato) and Enterobacter aerogenes. The technique depends on differences in metabolism of five carbon substrates-glycerol, inositol, lactose, glucose, and xylose-at two concentrations. Reproducibility is satisfactory and is monitored by the incorporation of control klebsiellae of known biotype.The method has been used for 12 months in the surveillance of urinary tract colonisation in this hospital. Gut carriage of klebsiellae, implicated by several workers as a source of infection, was common among staff and new admissions. Many biotypes were represented which were sensitive to most antibiotics except ampicillin.Klebsiellae, all multiply resistant, were isolated most frequently from urine specimens in two orthopaedic wards. In a longitudinal study in these wards, a sequential dominance in urinary tract colonisation by two klebsiella biotypes was shown, which suggested the presence of cross infection or an environmental reservoir. Confirmatory evidence was obtained from capsular serotypes and R-factor studies.Klebsiellae are one of the major causes of hospital acquired infection. This has led to the development of many methods which aimed to detect identical strains of the same species and thus provide a reliable method for epidemiological studies.Serological (Casewell, 1972;Riser et al., 1976; Palfreyman,1978) Received for publication 7 March 1979 Biochemical typing, however, if feasible, would be quick and inexpensive and could overcome the requirements for special reagents and special expertise often needed by other methods. Barr (1978) identified a number of biochemical test substrates whose differential metabolism provided good discrimination between isolates of klebsiella. In our experience, differential metabolism of these substrates also allowed discrimination between isolates of Enterobacter aerogenes. The various biotypes of Klebsiella pneumoniae (sensu lato) and Enterobacter aerogenes distinguished by the differential metabolism of five selected substrates are described here.This technique is applied to surveillance of biochemical types of klebsiella associated with colonization of the urinary tract. The results suggest that the preponderance of certain biotypes in some wards could be attributed to cross infection or to a common source. Material and methods ORGANISMS: ISOLATION AND IDENTIFICATIONA total of 445 clinical isolates of klebsiellae were examined over a 12-month period. These included 935 on 12 May 2018 by guest. Protected by copyright.

Biochemical and serological investigations on clinical isolates of klebsiella

“…Usually three or six biotypes are distinguished by biochemical typing (Cowan et al 1960;Edwards & Ewing, 1972). To subdivide Klebsiella strains into more distinct types for epidemiological purposes several authors have introduced biochemical typing schemes either by conventional test methods (Rennie & Duncan, 1974;Barr & Hogg, 1979;Haverkorn & Michel, 1979), or by commercially available biochemical test systems (de Silva & Rubin, 1977). The presence of multiple biotypes in single specimens and a biotype reproducibility of 640 were reasons for de Silva & Rubin (1977) questioning the value ofbiochemical typing ofKlebsiellapneumoniae.…”

Identification and Biotyping of Escherichia coli from Diarrheic Lambs in and Around Debre Birhan Town, Ethiopia

“…Biochemical reactions have conventionally been used for identification of bacteria to the species level. Extensive studies of sugar fermentation reactions of bacteria have been done to introduce biochemical typing systems in epidemiological studies of bacteria [13,14]. E. coli are able to ferment a variety of carbohydrate substrates, generally by converting them to glucose or to a substrate on the fermentative chain of the breakdown of glucose.…”

Evaluation of the stability of biochemical phenotypes of Escherichia coli upon subculturing and storage

“…The usefulness of these markers to subdivide strains below the species level, however, is greatly dependent on the variability of these characters within the species and the distribution of these variations (Lockhart & Liston, 1970). Extensive studies of the biochemical reactions of bacteria have been done to introduce biochemical typing systems in epidemiological studies of bacteria (Barr & Hogg, 1979;Krishnan et al, 1987;Crichton & Old, 1982). To achieve maximum discrimination, biotyping together with serotyping (Simoons-Smit et al, 1985 ;van der Waaij et al, 1976), serotyping and phage typing (Rennie et al, 1978), serotyping and fimbriation analysis (Brauner et al, 1987), serotyping and outer-membrane protein (OMP) analysis (Stenderup & 0rskov, 1983 ;Achtman et al, 1983) or sero/OMP/electrophoretic analysis of alloenzymes (Ochman & Selander, 1984) have been suggested for the study of epidemiologically important bacterial clones.…”