The survival of Streptococcus pyogenes on bacteriological swabs made from various fibres

Mean gestation at delivery and histological chorioamnionitis correlates with early-onset neonatal sepsis following expectant management in pPROM

This prospective observational study was carried out in India among 100 women with preterm pre-labour rupture of membranes (pPROM) between 26(0/7)-33(0/7) weeks on expectant management in order to correlate early-onset neonatal sepsis (EONS) with various features of chorioamnionitis. The incidence of pPROM during the study period of 1.5 years was 7%. The mean gestation at pPROM was 30(6/7) ± 1.8 weeks and at delivery was 32(1/7) ± 1 weeks. Features of chorioamnionitis in the form of clinical, microbiological, histological or a combination of these were observed in 70/100 women. Clinical chorioamnionitis was seen in 16%, bacterial isolates were present in 30% on cervical swab and in 39% on placental membrane culture and 19% had histological chorioamnionitis. EONS was present in 23/97 (24%). Clinical chorioamnionitis (p = 0.069), bacterial isolates on cervical swab (p = 0.56) or placental membranes (p = 0.39) were not found to predict EONS; whereas histological chorioamnionitis (p = 0.002) and lower gestation at delivery (p = 0.013) were significantly associated with EONS.

Lower genital tract swabs in the prediction of intrauterine infection in preterm prelabour rupture of the membranes

OBJECTIVE

To examine the genital tract flora in women with preterm prelabour rupture of the membranes and to determine the relationship of these microorganisms to those found in fetal blood and amniotic fluid.

DESIGN

Prospective study of 97 patients with preterm prelabour rupture of the membranes.

SETTING

Maternal-fetal medicine centre.

METHODS

High vaginal and endocervical swabs were taken for routine culture of aerobic and anaerobic bacteria and Ureaplasma urealyticum and Mycoplasma hominis. Cordocentesis and amniocentesis were performed and fetal blood and amniotic fluid were cultured for aerobic and anaerobic bacteria. Amniotic fluid was also cultured for Mycoplasma spp. The sensitivities and specificities of genital tract colonisation in the prediction of fetal blood and amniotic fluid infection were calculated.

RESULTS

Positive genital tract cultures for aerobic and anaerobic organisms predicted 40% of positive fetal blood and 53% of positive amniotic fluid cultures with false positive rates of 24% and 25%, respectively. The sensitivity and false positive rates for genital tract colonisation with Mycoplasma spp in the prediction of amniotic fluid infection with these organisms were 85% and 35%, respectively.

CONCLUSIONS

In preterm prelabour rupture of the membranes lower genital tract cultures provide poor prediction of intrauterine infection.

Contaminated first-aid dressings: report of a working party of the PHLS

In a collaborative study 12 Public Health Laboratory Service laboratories and the Division of Hospital Infection, Central Public Health Laboratory, investigated the degree of contamination of standard dressings produced by manufacturers in India or in England by a comparison of the results of culture of 25 sterilized dressings with those of 25 untreated dressings. Of the 38 batches of dressings made in India 27 (71%) were judged contaminant and another six could be so judged when Bacillus species were examined. In two batches laboratory contamination precluded a judgement and only three batches passed the test. Of the 27 batches made in England, only three gave any evidence of contamination at the lowest level of significance. Repeat investigation of one of these batches gave no evidence of contamination. Organisms of the genus Bacillus and fungi were associated with contamination; micrococci and propionibacteria were laboratory contaminants. There was evidence for both failure and sterilization and of contamination after sterilization during the manufacture of dressings.

The recovery of anaerobic bacteria from swabs

When a standard sample of simulated exudate containing known numbers of anaerobic bacteria was taken up on a swab and plated on solid medium, the number of colonies subsequently cultured represented a very small proportion of the original sample. Evidence is produced that the apparent loss is not primarily attributable to inactivation on the swab but rather to retention of organisms on the swab. This was demonstrable with Clostridium welchii and with Bacteroides species that have hitherto been regarded as relatively oxygen-sensitive.When stock strains of Bacteroides species were held for some hours on swabs, some progressive loss of viability was demonstrable. A measure of protection was afforded when these organisms were held aerobically on blood agar medium, but a very exacting anaerobe and some wild strains of faecal anaerobes showed gradual inactivation under these conditions.These findings may have important implications in relation to currently employed bacteriological sampling procedures with swabs in clinical practice.