Microbial gut overgrowth guarantees increased spontaneous mutation leading to polyclonality and antibiotic resistance in the critically ill

Polyclonality is defined as the occurrence of different genotypes of a bacterial species. We are of the opinion that these different clones originate within the patient. When infections and outbreaks occur, the terms of polyclonal infections and polyclonal outbreaks have been used, respectively. The origin of polyclonality has never been reported, although some authors suggest the acquisition of different clones from different animate and inanimate sources. We think that the gut of the critically ill patient with microbial overgrowth is the ideal site for the de-novo development of new clones, following increased spontaneous mutation.

Low-dose vancomycin prophylaxis reduces coagulase-negative staphylococcal bacteraemia in very low birthweight infants

Very low birthweight (VLBW) infants undergoing neonatal intensive care are at risk of infection with coagulase-negative staphylococci (CONS). This study investigates the efficacy of twice daily, 1 h infusions of vancomycin (5 mg kg) in reducing CONS infection in VLBW infants receiving parenteral nutrition. Of 72 infants in the study, 37 were randomized to vancomycin and 35 to the control group. Clinical variables and mortality were similar in both groups. In the vancomycin group, 11 infants had one or more episodes of CONS bacteraemia compared with 17 in the control group. Two babies in the treatment group had more than one episode of CONS bacteraemia, compared with nine in the control group (P = 0.02). There were 13 episodes of CONS bacteraemia in the vancomycin group compared with 29 in the control group. When only positive blood-cultures associated with a rise in C-reactive protein were considered, there were six episodes of CONS bacteraemia in the vancomycin group compared with 18 in the control group. Similarly there were five infants with one or more CONS infections compared with 11 in controls and one with more than one episode compared with six in the control group (P = 0.05). Prophylaxis with intermittent low-dose vancomycin infusions may help reduce recurrent CONS bacteraemia in VLBW infants receiving parenteral nutrition.

Selective decontamination with nystatin for control of a Candida outbreak in a neonatal intensive care unit

Selective decontamination of the digestive tract (SDD) with oral nystatin was evaluated as a measure to control an outbreak of Candida infection in a neonatal intensive care unit (NICU). Seventy-six out of 106 neonates who carried Candida spp. received the main study manoeuvre (the application of oral nystatin in the throat and stomach) during the 12-month open trial. One third of the neonates weighed < 1500 g whilst about half were being ventilated. The mean stay was 33.2 d (SD +/- 46.9). Two cases with candidaemia within a fortnight were associated with a yeast carriage rate in the NICU of about 50%; more than 80% of the isolates were Candida parapsilosis. During the implementation period there were four new neonates with fungaemia caused by C. parapsilosis. Once the carriage rate dropped below 5% (P < 0.001), no new cases of systemic infection with the outbreak strain were recognized in the following 8 months. It took 3.5 months to control the outbreak. The observation that all other clinical diagnostic samples were free from Candida suggests that translocation from throat or gut into the systemic circulation occurred. SDD with oral nystatin was effective in reducing the yeast carriage index (mean index 1.93, before SDD; 0.45, after SDD; P < 0.001). A significant reduction of carriage, both in rates and indices, is thought to have contributed to the control of this candida outbreak.

Neonatal meningococcal conjunctivitis associated with meningococcal meningitis

Two infants are described in whom identical strains of meningococcus were isolated from both the eyes and the cerebrospinal fluid. This suggests that the eye may be a portal of entry in at least some cases of perinatally acquired neonatal meningococcal disease and has important implications for the management of purulent conjunctivitis in the newborn.

Reducing disinfectant wastage

In order to lower departmental costs in an ophthalmological outpatient department by reducing wastage, the stability of available chlorine at levels of 280 ppm and 560 ppm in litre solutions of sodium dichloroisocyanurate was investigated over a three-week period. There was no significant decay in available chlorine at these levels in solutions kept at 20 degrees C. Sodium dichloroisocyanurate may be prepared on a weekly instead of a daily basis with an annual saving of 1200 pounds to 1400 pounds.

Ciprofloxacin in neonatal Enterobacter cloacae septicaemia

Multiresistant Enterobacter cloacae infection in six premature infants was eradicated with intravenous ciprofloxacin (10 mg/kg/day). Bacterial resistance did not develop. Adequate plasma ciprofloxacin concentrations were achieved in all treated patients. No clinical evidence of side effects was observed.

Outbreak of cephalosporin resistant Enterobacter cloacae infection in a neonatal intensive care unit

Enterobacter cloacae resistant to third generation cephalosporins emerged rapidly during an outbreak of serious infections due to this organism in a neonatal intensive care unit where ampicillin and gentamicin were used as first line antibiotic treatment. Organisms resistant to cephalosporins were isolated from 12 infants, six of whom developed systemic infection. Two infants died. Isolates of E. cloacae from four of five infants treated with cefotaxime showed a loss of sensitivity to this antibiotic during treatment, but in the three infants who survived sensitive organisms were again isolated after treatment had stopped. Stopping treatment with the cephalosporins, closure of the unit to new admissions, and strict cohorting of colonised infants resulted in a prompt end to the outbreak. This outbreak suggests that the routine use of third generation cephalosporins for suspected sepsis may be inappropriate in the presence of a large reservoir of organisms with the potential for rapidly developing resistance. Routine bacteriological surveillance, however, might permit their use on a rotational basis.

Antibiotic sensitivities of urinary pathogens isolated from patients in Liverpool, 1984-5

Urinary pathogens isolated from patients in general practice, an antenatal clinic and several hospitals in Liverpool during 1984-5 have been tested for antibiotic sensitivities. The proportion of sensitive organisms varied from antimicrobial to antimicrobial and from institution to institution. Isolates from all institutions showed high rates of sensitivity to cephradine, nalidixic acid and nitrofurantoin, and somewhat lower rates to trimethoprim. Significantly lower sensitivities were found to ampicillin and sulphamethoxazole indicating that neither ampicillin nor a sulphonamide is suitable for initial choice on a 'best guess' basis in the situation studied. In general, the organisms derived from the antenatal patients showed the highest rates of sensitivity and those isolated from patients in geriatric hospitals the lowest.

Infection and colonisation of neonates by Hansenula anomala

Over a 13-month period 52 neonates (10% of those admitted to the Mersey Regional Neonatal Intensive Care Unit) were found to be colonised with the ascosporagenous yeast Hansenula anomala. 8 babies became infected, all but 1 of whom were heavily colonised before infection. 7 of the 8 infected babies were of very low birth-weight (less than 1500 g). All 8 had multiple problems associated with low birth-weight and prematurity and were kept in the intensive care unit. 5 babies had fungaemia, 2 had fungaemia and ventriculitis, and 1 had ventriculitis only. In each case H anomala was the sole pathogen isolated. Anti-Hansenula antibodies developed in 5 babies within 3 months of infection. Infected babies were successfully treated with a combination of 5-flucytosine and amphotericin B. Despite extensive searches the babies appeared to be the only reservoir of the yeast.

Antibiotic sensitivity of enteropathogenic bacteria isolated from patients in a Sharjah hospital

In recent years widespread circulation of salmonella and shigella strains resistant to multiple antibiotics has become an international problem. Accordingly the bacterial sensitivity to a range of antibiotics has been assessed in vitro and recorded for the period 1979-83 for patients from the Al Qassimi Hospital. A total of 229 enteric pathogens from 148 children and 59 adult patients were isolated and studied. Most of the enterobacteria were sensitive to colistin, gentamicin, trimethoprim and chloramphenicol (Salmonella typhi approached 100% sensitivity). High rates of sensitivity were also found to ampicillin in S. typhi (96%) and other salmonella serotypes (85%), whilst only 57% of Shigella species and 14% of Escherichia coli were sensitive to this antibiotic. Low rates of sensitivity to sulphamethoxazole, streptomycin and tetracycline were found in shigella and E. coli (ranging from 7 to 14%). Approximately 50% of S. typhi and other salmonella serotypes were sensitive to sulphamethoxazole and streptomycin and 80% to tetracycline. Resistance to three or more antibiotics was very common in shigella and enteropathogenic strains of E. coli (74-85%), less common in non-typhoid salmonella (29%) and exceptional in S. typhi strains. In general, shigella and E. coli isolates showed a high rate of resistance to several antibiotics, whilst S. typhi and other salmonella serotypes retained their original sensitivity to most of the antibiotics used in clinical practice.

Comparative trial of trimethoprim and co-trimoxazole in recurrent urinary infections

Eighty-nine patients with a history of recurrent urinary infection who required immediate treatment for significant bacteriuria were treated with either trimethoprim (300 mg at night) or with the standard course of co-trimoxazole (two tablets 12-hourly) for seven days. Cure rates one week after the end of treatment were 74.4% and 80.4%, respectively. During the following month the relapse rate was lower in the group given trimethoprim than among those who had received co-trimoxazole. Consequently, the cure rates six weeks after the start of treatment were 71.4% in the trimethoprim group and 58.5% in the co-trimoxazole group. These results suggest that in this type of patient, it may be possible to reduce the incidence of bacteriological relapse by giving antibiotics in larger doses and at less frequent intervals than are at present generally recommended.

Studies on antibody to hepatitis A virus in children and adults in London

366 specimens of serum from children and adults without liver disease were screened for antibody to hepatitis A virus (anti-HAV) by means of radioimmunoassay. 56% were born in London, 26% came to London from various parts of the United Kingdom and the remainder (18%) from various parts of the world. The prevalence of antibody was related to increasing age, ranging from 7% in children under ten years of age to 77% in adults aged 50 years or more. The prevalence of anti-HAV was significantly higher in females, in the lower socio-economic class and in those not indigenous to London. In comparison to other urban populations such as those of the United States and Western Europe, the prevalence of anti-HAV was similar in terms of the overall prevalence and age distribution. By contrast, these findings were entirely different from the countries of Eastern Europe and the Middle East where the overall prevalence was higher but the anti-HAV was equal in all ages. Thus, the findings presented indicate that hepatitis A virus infection is common in London and also shows a clear relationship to advancing age, lower socioeconomic class and the country of origin.

Studies on the stability of antilymphocyte globulins

An account is given of the effect of storage under various conditions on the physical and immunosuppressive properties of antilymphocyte globulins. No loss of in vivo immunosuppressive potency was shown by horse antimouse lymphocyte globulin when stored for up to 2 years in a liquid, frozen, or lyophilised state. Similar studies on horse antihuman lymphocyte globulin showed no loss of in vitro activity, as measured by an immunofluorescence test. Ultracentrifugal analyses showed no increase in aggregate when antilymphocyte globulin was stored liquid or freeze-dried at 4 degrees C. Storage experiments at abnormally high temperatures demonstrated that under these conditions freeze-dried horse antihuman lymphocyte globulin was stabilised by the presence of glucose (4.6%w/v). Antilymphocyte globulin lyophilised in the presence of glucose showed improved solubility properties as compared with material dried from saline.

Thermal inactivation of diphtheria toxoid following drying by sublimation in vacuo

The Lf values of diphtheria toxoid alone and in combination with tetanus toxoid or tetanus toxoid plus pertussis vaccine, dried by sublimation in vacuo, sealed under nitrogen, exposed to elevated temperature and rehydrated thereafter were not altered. Lf values declined in samples sealed under air. The values for Kf in the above preparations increased in relation to increased temperatures of exposure for a given time or following exposure to a given temperature for increased time intervals. The sensitivity of the system of testing used was greater following the addition of ‘helper’, a fast flocculating solution of diphtheria toxin, and in the case of dried diphtheria toxoid stored under adverse conditions (sealed under air) for two years, the addition of ‘helper’ was necessary to obtain a flocculation reaction. In general, the results obtained indicated a very high stability for preparations sealed under nitrogen, and a significantly lower stability for preparations sealed under air.