Routine Bacteriology Research Articles

The management of pyodermas.

With the rising cost of medical services, it was decided to reassess the relevance of routine bacteriology investigations to the management of the individual patient with pyoderma. In both prospective and retrospective studies, it was found that laboratory reports were simply confirmatory and did not contribute to the management of the individual patient. A call is made for physicians to continuously look for cheaper ways of managing patients without necessarily causing any disservice to the patient.

Estimation of the bacteriological quality of fish by automated conductance measurements

The rapid automated conductance assay system has been used in experiments concerned with estimating the bacteriological quality of fish in terms of total and selective counts. Results of the former method were obtained in one-fifth of the time taken by conventional methods and the correlations between the methods were good. Selective counts of Escherichia coli, coliforms, and vibrios were completed in one-third of the normal time. The instruments were easy to use and the results easy to interpret. The method holds out good promise for automating such routine fish bacteriology.

Clostridium difficile-associated diarrhoea

During the course of 1 year, Clostridium difficile was isolated from 145 (4 per cent) of 3591 faecal specimens submitted to a hospital routine bacteriology laboratory. These C. difficile positive specimens came from 95 patients or 10.99 per cent of 864 patients investigated for suspected gastroenteritis. In a control population of 318 persons C. difficile was isolated from only 10 of them or 3.1 per cent; this difference was statistically significant. We conclude that as this increase in the isolation of C. difficile from patients with diarrhoea is significant and is about as frequent as that of Campylobacter spp., faecal specimens submitted for routine bacteriology should also be cultured for C. difficile . As with diarrhoea caused by other enteric pathogens, most C. difficile -associated episodes of diarrhoea are mild and spontaneously reversible but approximately 20 per cent of patients have prolonged diarrhoea and may benefit from treatment.

Symptomatic and asymptomatic rotavirus infections in hospitalized children.

During one year, 871 infants and children admitted to a Dutch paediatric ward were examined weekly for rotavirus. Rotavirus was detected in the stools of 64/129 (49.6%) children with diarrhoea and in 283/742 (38.1%) controls. The incidence of asymptomatic rotavirus excretors increased from 14.5% in infants 0 to 6 months of age to 65.8% in children of 6 years and over, a feature not yet reported. Possible explanations may be the methodology used, the age groups studied, the local hospital (and community) situation and the geographical location. Routine bacteriology revealed enteropathogens in 25.6% of the children with diarrhoea: Salmonellae in 20.9%, Campylobacter jejuni in 3.9%, Yersinia enterocolitica in 1.5%, Shigella sonnei in 0.8% and enteropathogenic E. coli in 0.8% of the patients.

Diarrhoea in Swedish infants. Aetiology and clinical appearance.

Ninety-five children with gastroenteritis admitted at the Department of Paediatrics, Malmö General Hospital, Malmö, Sweden, starting November 1978 through October 1979 were studied. Patients were examined clinically and the course of their disease was followed. Stool specimens from all patients were analysed by routine bacteriology and rotavirus identification was done by immune-electroos-mophoresis. Fifty-eight per cent of patients had rotavirus. Campylobacter was found in 6%, enteropathogenic E. coli in 2%, Yersinia enterocolitica in 2% and Salmonella in 1% of patients. Stool specimens from 53 healthy children matched for sex and age served as controls for bacterial pathogens. All were negative. Forty per cent of patients presented with a clinical dehydration, but only 11%-half of them with bacterial enteropathogens-needed i.v. therapy and 4% required antibiotic treatment. Median time for hospitalization was three days. Vomiting, fever, watery diarrhoea and initial clinical dehydration were more commonly associated with rota virus infection. Macroscopic blood in stools was restricted to patients with bacterial aetiology.

Aetiology and Clinical Features of Severe Infantile Diarrhoea in Addis Ababa, Ethiopia

This study, performed at Ethio-Swedish Pediatric Clinic, Addis Ababa, Ethiopia, from March through June 1979, included 175 children with diarrhoea in need of parenteral rehydration and 74 age and sex matched controls. Stool samples were analyzed using microscopy, routine bacteriology including culture for Campylobacter fetus ss jejuni, enterotoxin bioassay (LT) and rotavirus analysis. The clinical appearance of patients and stools was recorded. A microbiological diagnosis was established in 70% of the patients as compared to 23% positive findings in the controls. The most common findings were rotavirus (49%), enteropathogenic E. coli (EPEC) (19%) and Campylobacter (13%) of the patients. Among bacterial enteropathogens EPEC was the most prevalent. The isolation rate of enterotoxigenic bacteria was 9% in patients, not differing significantly from the controls, 7%. The correlation of clinical symptoms to aetiology was not conclusive suggesting that the clinical picture of infantile diarrhoea in most cases is nonspecific.

Extrapulmonary tuberculosis: a potential source of laboratory-acquired infection.

A three-year retrospective study has demonstrated the effect of extrapulmonary tuberculosis on safety within a routine bacteriology laboratory. The investigation showed that, from 112 patients, 162 specimens considered to present a risk to laboratory staff were processed outside of the B1 protective area. However, it was estimated that only 51 of those specimens were heavily positive. Of these 57% were sputum 30% pus, and 10% urine. Specimens of pus and urine account for 50% of specimens received for non-tuberculosis investigations, and it would be impossible to process all specimens that might present a risk in B1 accommodation and still maintain a high degree of safety. It is recommended that request forms which accompany specimens should clearly indicate potential high-risk specimens.

Evaluation of the phenol-induced flagellar agglutination test for the identification of the cholera group of vibrios.

Applied routinely to 1081 recently isolated cultures, the phenol-induced slide-agglutination test (standard procedure) with flagellar antiserum corrently identified 98.9% of Vibrio cholerae strains of O type-I and NAG serotypes; 1.0% of cultures were unstable in phenol-saline. The incidence of instability and other types of defect was higher (7.3%) in older stock cultures. The majority of such strains were successfully tested by one of the three modified procedures. No cross-reactions were observed in 47 cultures of other species including the halophilic vibrios. Only one out of the 1205 cultures of V. cholerae tested by all procedures reacted negatively; this strain was found to lack functional flagella. These results establish the significance of flagellar specificity as a classificatory determinant in V. cholerae, and the fidelity and utility of the phenol test in routine bacteriology.

The identification of gram-negative anaerobic bacilli isolated from clinical infections

Gram-negative anaerobic bacilli isolated from specimens submitted to the routine diagnostic bacteriology laboratory and regarded as significant pathogens were identified by conventional bacteriological tests; 399 strains isolated from 356 specimens submitted from 332 patients were studied and most were readily identified by the results of a combined set of morphological, biochemical, tolerance and antibiotic disk resistance tests; B. fragilis has particular pathogenic potential and was the commonest species isolated, accounting for greater than 50% of strains. The next commonest was B. asaccharolyticus with 55 strains, and 16 other species or groups were represented by smaller numbers. Many (68%) were from infections related to the gastro-intestinal tract, but there were significant numbers from infections of the male and female genito-urinary tracts, the head, neck and central nervous system and from a variety of soft tissue infections. Most infections were mixed, and a pure culture of a Bacteroides sp. was obtained from only 26% of infections; two or more strains of Bacteroides were recovered from 55 infections. The specific identification of Bacteroides may help the bacteriologist to judge the significance of laboratory findings, influence the patient's management and prognosis and help determine the source of infection.

RAPID DIAGNOSIS OF BACTEROIDES INFECTIONS BY INDIRECT IMMUNOFLUORESCENCE ASSAY OF CLINICAL SPECIMENS

43 specimens from a variety of sites were directly examined by indirect immunofluorescence assay (I.F.A.) with specific antisera against the capsular polysaccharide of Bacteroides fragilis and pooled antisera against a number of serotypes of Bacteroides sp. (all of the former B. fragilis subspecies). The findings were compared with those of routine anaerobic bacteriology and gas liquid chromatography for short-chain fatty acids. Examination by I.F.A. was a sensitive (100%) and specific (90·3%) means of identifying B. fragilis. Use of the pooled serum was sensitive (100%) but less specific (64·3%) than the capsular antiserum (90·3%) although it had the advantage of detecting Bacteroides species other than B. fragilis. The capsular serum I.F.A. gave 9·7% false positives and no false negatives. The predictive value of a positive identification of B. fragilis in a clinical specimen using this anticapsular serum I.F.A. test was 80%; with the pooled Bacteroides group-serum it was 60%. The predictive value of a negative test was 100% for both sera, indicating that a negative I.F.A. test is a reliable index of the absence of Bacteroides from the culture I.F.A. of clinical material provides a rapid (<2 h) specific and sensitive means for the diagnosis of B. fragilis infections and would be of use in a clinical laboratory.

Differentiation of Bacteroides fragilis species by gas chromatographic detection of phenylacetic acid.

Of 382 strains tested, 261 strains of the species Bacteroides fragilis, B. thetaiotaomicron, B. ovatus, and B. distasonis produced phenylacetic acid; the remaining strains, belonging exclusively to the species B. vulgatus, failed to do so. This differentiation characteristic may be useful in routine clinical bacteriology.

A computer-assisted bacteriology reporting and information system.

A computer system for reporting and recording all specimens processed by the routine bacteriology laboratory at the Royal Postgraduate Medical School is described. Features of interest are the method of input using a mixture of 3-character alphanumeric codes and numbers, cumulative reporting to the wards, and selective listing of relevant previous results for the patient, which is available to technical and supervisory staff during processing of the specimen. The relative value to the wards and the laboratory of each type of information transfer has been assessed. Overall the use of a computer has resulted in higher quality bench work and more accurate reporting. It seems little more expensive than a previous manual system, although it has transferred work from the technical to the clerical staff.

The bactlab system — A data system for bacteriological routine

An implemented version of a data system for routine bacteriology is described which uses punch cards to capture all administrative data and OMR (optical mark recognition) documents for the bacteriological findings: diagnosis, antibiotic sensitivity patterns, phage type etc. The output includes reports for the customers and report lists for the laboratory, as well as surveys over findings of pertinent bacteria produced twice each month. In addition bills are produced at regular intervals, both for hospitals and for private patients. All results are stored on magnetic tape in order to make later analysis possible. The system has also been adapted for use in a research project for the study of postoperative infections.

An assessment of one year of computer-assisted microbiology reporting at Charing Cross Hospital.

The pilot scheme began in August 1972 after three months of running parallel with a conventional system. In October 1972 the system was moved from Fulham Hospital into the new Charing Cross Hospital. Sixty thousand routine bacteriology requests have been processed satisfactorily by the computer system, about 70% of the total received. The cost for a computer-printed report is 32p compared with 6p for a typed one.

An Automatic Bacteriological Test Bed

This is a description of progress on an automatic machine for routine bacteriology now being developed under the auspices of the National Research Development Corporation at the Hatfield Polytechnic. Although the work reported here is in no sense complete, it has already been possible to link components from existing miniaturized techniques into a mechanical process and to build a small computer-controller which will play a central role in the developing system.

A data processing system for hospital bacteriology.

A system for the automatic capture and retrieval of information contained in routine bacteriology reports is described. The system depends on the preparation of reports on an electric typewriter producing punched paper tape as a byproduct. Periodically the information contained on the tape is analysed by computer. The potential value of the system for the analysis of the results of antibiotic sensitivity testing and for the study of the epidemiology of hospital infections is briefly discussed.

The isolation of Neisseria sp. from pneumonic sheep lungs.

Extract Sir,—In the course of routine bacteriology on pnemonic sheep lungs, a Neisseria sp. has been isolated on a number of ocassions both on its own and together with Pasteurella haemolytica. As a result of the isolation of this Neisseria sp. and because of the absence of reports in the veterinary literature of such isolations, it was decided to examine fresh abbatoir material.

The differentiation of Enterobacteriaceae infecting the urinary tract: A study in male paraplegics

Methods adopted in a routine bacteriology laboratory for the rapid identification of Enterobacteriaceae isolated from urine are described. The incidence of various bacteria causing infection in paraplegics after catheterization of the bladder is recorded, Klebsiella accounting for the majority of infections caused by lactose fermenters and Providence for the majority of ;paracolon' infections. The importance of these bacteria in cross-infection is discussed.

Antibiotic sensitivity patterns of common pathogenic organisms.

This report is concerned with the sensitivity pattern to various antibiotics of a number of bacteria commonly encountered in the routine bacteriology laboratory. These micro-organisms, totaling 784, were isolated from various clinical sources over a 9-month period during 1959 and 1960. All of the specimens were submitted because of known or suspected infection. An attempt has been made to correlate the sensitivity pattern of some of the strains with their source. The importance of the concentration of the antibiotic used in determining the sensitivity pattern of a specific organism is also emphasized. Materials and Methods All of the organisms were obtained from specimens routinely submitted by various clinical services. Following recent recommendations 5 no attempt was made to differentiate Staphylococcus into var. albus and var. aureus. The coagulase test was performed with a commercially obtained lyophilized product. * The type of hemolysis of Streptococcus was based on the surface appearance on

Escherichia coli diarrhea: The relationship of certain serotypes of escherichia coli to sporadic and epidemic cases of infantile diarrhea

Summary 1. Certain serotypes of Esch. coli can produce diarrhea in infants. 2. In an attempt to establish the etiology of an infant's diarrhea, it is essential to perform routine serotyping of the Esch. coli isolated from the infant's stool. 3. Esch. coli serotyping is simple to perform and can be done in any routine bacteriology laboratory. 4. Esch. coli diarrhea may spread rapidly through hospital wards despite the use of modern isolation techniques. 5. Patients with Esch. coli diarrhea cannot be distinguished on clinical grounds from patients with nonspecific diarrhea. 6. The treatment of patients with Esch. coli diarrhea consists in the employment of well-established principles of treatment of infantile diarrhea plus the administration of oral neomycin.