A brief history of infection control - past and present.

The scientific study of hospital or nosocomial cross-infection began during the first half of the 18th century, and from that time until the start of the 'Bacteriological Era' many of the most notable contributions originated in Scotland. However it was only 100 years later in 1858 that Florence Nightingale promoted the case for hospital reform. The real understanding of hospital infection followed upon the discoveries of Pasteur, Koch and Lister and the beginning of the 'Bacteriological Era'. The close of the 19th century saw the triumphs of hospital reform and asepsis and seemed to herald the final victory over hospital cross-infection. However, the victory was short-lived. It was soon realised that infections occurred not only in obstetric and surgical patients, but in medical patients as well, and that air could also be a source of infection. Streptococcal, staphylococcal and then Gram-negative bacilli as a cause of hospital infection became a focus of attention, as did antibiotic-resistant organisms. This paper looks briefly at the establishment of the control of infection doctor, infection control committee and infection control nurse as well as summarising the changes, problems and advances in infection control up to the present time.

How best to utilize limited resources.

South Africa's new health policy embraces the primary health care (PHC) approach for all its peoples and will include good primary, secondary and tertiary care. The policy will hope to provide the highest possible standards of care, yet be of a scale and complexity that the country can sustain into the future. There will almost certainly be rationalization of many of the tertiary teaching hospitals, with inevitable cut-backs in their budgets. This in turn could carry the risk of damage to the fabric of these institutions, which might be impossible to repair. Medicines offer a simple, cost-effective answer to many health problems in Africa, provided they are available, accessible, affordable and properly used. A looming problem in African drug markets is inefficiency and waste. The use of counterfeit medicines has reached unparalleled heights. It is vital that there should be a competent, honest, accountable and independent national drug regulatory authority, secured in law, to provide the necessary infrastructure for the acquisition of sound medicines. Medicines are central to a sound national health policy, but there is great public concern about their costs. Anti-infective drugs are amongst the most widely used class of drugs in the world. Inappropriate use of these agents is widespread and guidelines need to be established for their correct use. The control of all medicines in South Africa is governed by the Medicines & Related Substance Act of 1965. The Medicines Control Council is mandated to ensure that all medicines (including antibiotics) available to the public are efficacious, safe and of high quality. An informally-constituted Antibiotic Study Group has been established in order to monitor aspects of antibiotic therapy that impinge on more general issues of public health, country-wide. The Antibiotic Study Group has instituted an Antibiotic Surveillance Programme to monitor the development of antibiotic resistance nationally. In addition the majority of the tertiary teaching hospitals have comparable in-house antibiotic control policies to help prevent such resistance and to cut costs. These issues need to be debated and resolved. Once in place and working effectively, they will in the long-term supply the most cost-effective means of providing health care for all.

Microbiological surveillance during selective decontamination of the digestive tract (SDD)

The use of selective decontamination of the digestive tract (SDD) as prophylaxis against nosocomial respiratory tract infection remains controversial, largely because of concerns that, in the long term, it may promote the emergence of antibiotic-resistant strains. This report describes the results of surveillance cultures and susceptibility testing undertaken during the course of a 2-year, double-blind study of the efficacy of SDD which was conducted in a respiratory intensive care unit (ICU). Surveillance specimens from the alimentary tract and trachea were obtained from each patient on admission and then twice weekly until 48 h after discharge from the unit. Specimens were cultured semiquantitatively and organisms from morphologically distinct colonies were identified by standard methods; the susceptibilities of these isolates were determined by the disc diffusion method. Five thousand, nine hundred and sixty surveillance samples from 239 patients were processed in this way. Compared with the placebo group, SDD caused a significant reduction in the incidence of colonization of the alimentary tract with aerobic Gram-negative bacilli (AGNB), and Candida spp. were almost totally eliminated. The incidence of colonization with enterococci increased in both groups, while the incidence of both colonization of the alimentary tract with strains of coagulase-negative staphylococci and methicillin-resistant Staphylococcus aureus and infection caused by these organisms increased in the SDD group. Acinetobacter spp. were the most common bacteria associated with unit-acquired colonization and lower respiratory tract infection in both groups. The acquisition of strains of Pseudomonas aeruginosa and cefotaxime- and/or tobramycin-resistant Enterobacteriaceae was significantly greater in the placebo group than in the SDD group, although tobramycin-resistant strains of Proteus, Morganella and Providencia spp. were isolated from three of 114 patients receiving SDD. The use of SDD did not lead to an overall increase in antibiotic resistance amongst the AGNB usually associated with ICU-acquired infection. However, colonization with strains which were either resistant to one or more of the antibiotic components of the regimen or which were not inhibited by the regimen was observed and may subsequently lead to infection.

Lowbury Lecture. Infection control--a challenge in a land of contrasts.

The general level of health care in any country will dictate to a large extent the amount of attention paid to the control of nosocomial infections. In South Africa the apartheid era, although initially supporting a strong economy, did little to foster a good education system among the mass of the population. With the imposition of sanctions and the decline in the economy, the health services which had been curative in nature and centred around the medical schools of the country and their teaching hospitals, began to suffer the effects of rampant inflation and financial cutbacks. Nevertheless, virtually all the medical schools support infection control programmes of one sort or another. In addition, there are a number of Infection Control Societies in the country. With the present political instability and violence in the country, the health services have not escaped. Staff cutbacks are inevitable and wards may have to close; the academic hospitals are under threat. Privatization is strongly favoured by government. The present population of approximately 30 million could double by the year 2020, putting enormous pressure on limited resources. The squatter problem worsens every month. The spectre of human immunodeficiency virus (HIV) infection increases yearly. Any assessment of priorities must therefore be made against this background. Only proven methods of infection control should be encouraged. In the light of the foregoing, three areas of practical activity are examined: the re-processing of heat-labile equipment, the re-use of disposables and the disposal of clinical waste.(ABSTRACT TRUNCATED AT 250 WORDS)

Double-blind study of selective decontamination of the digestive tract in intensive care.

Selective decontamination of the digestive tract (SDD), by means of non-absorbable antibiotics, to prevent infection in intensive-care units (ICUs) remains controversial; there is evidence that the regimen reduces the incidence of secondary infection, but no convincing reduction in morbidity or mortality has been shown and the costs and effect on microbial resistance patterns need further study. In a double-blind, placebo-controlled trial, we have tried to find out whether SDD should be used routinely in all ICU patients at high risk of secondary infection. All patients admitted to the ICU who were thought likely to stay in the unit for at least 5 days and to need intubation for longer than 48 h were enrolled and randomly allocated to groups receiving placebo or SDD (amphotericin, colistin, and tobramycin applied to the oropharynx and enterally); all patients received intravenous cefotaxime for 72 h. Of 322 patients randomised, 83 were withdrawn (80 ICU stay or duration of intubation too short, 3 protocol violations). 239 medical, trauma, and surgical patients completed the trial period (114 SDD, 125 placebo). There were no differences between SDD and placebo groups in incidence of infection (30 [26%] vs 43 [34%] patients; p = 0.22), duration of ICU stay (mean 16.2 [14.3] vs 16.8 [12.3] days), hospital stay (29.9 [SD 25.0] vs 31.9 [22.2] days), or mortality (21 [18%] vs 21 [17%]). SDD substantially increased the costs of intensive care. Mechanisms other than bacterial colonisation of the gut may bring about substantial numbers of secondary infections in ICUs. Routine use of SDD in multidisciplinary ICUs cannot be recommended.

Intensive care management of community-acquired Klebsiella pneumoniae.

The clinical features of 18 patients with Klebsiella pneumoniae requiring intensive care unit (ICU) management are presented. All patients required ventilatory support; 17 were given constant positive pressure ventilation and 10 required greater than 10 cm positive end expiratory pressure. The clinical picture was characteristic: pre-existing medical disease, clinical features of severe pneumonia and copious purulent bronchial secretions, Gram--ve organisms on Gram's stain and lobar consolidation on the chest radiograph were common. Septicaemic shock, confusion and uncompensated metabolic acidosis were the presenting clinical features predicting a poor outcome. Antimicrobial chemotherapy, that combined an aminoglycoside and a third generation cephalosporin to ensure adequate early antibiotic serum levels, may help to improve the prognosis.

Influence of amikacin as the primary aminoglycoside on bacterial isolates in the intensive care unit.

Amikacin was introduced as the primary aminoglycoside in our hospital to prevent the further development of multiply resistant Gram-negative organisms. This study compares clinical and microbiological data before and after institution of this policy to evaluate the influence on clinical outcome in patients as well as changing resistance patterns in the respiratory ICU. Patient populations were similar in terms of severity of illness (Acute Physiology and Chronic Health Evaluation II scores), age, ventilation, invasive procedures, and the incidence of various diseases. We found that the rate of amikacin resistance increased from 8.5% to 39.6% with an increase in resistance to tobramycin (19.3% to 33.3%) and netilmicin (23.9% to 47.9%) over the same period despite minimal usage of these drugs. The clinical outcome was similar in the periods contrasted. Our findings suggest that restricting aminoglycosides to amikacin only resulted in increasing Gram-negative resistance although there was no significant effect on patient outcome.

Imipenem/cilastatin in the treatment of severe nosocomial pneumonia.

Imipenem/cilastatin (Tienam 500; Logos) 1 g, administered intravenously every 8 hours, was evaluated in an open clinical trial in 35 patients with severe nosocomial pneumonia. In 84.4% of cases there was a favourable clinical response; microbiological success was achieved in 63.3% and partial success in 20% of patients. The majority of Gram-negative and Gram positive organisms were sensitive to imipenem, including those resistant to the aminoglycosides. Although colonisation was frequent, superinfection was uncommon. Imipenem was well tolerated in these critically ill patients, many of whom had renal and other organ failure. The wide spectrum of antimicrobial activity and minimal side-effects made it a useful agent in patients with severe nosocomial pneumonia.

Treatment of neurosyphilis. A comparison of penicillin regimens.

Recommendations for treatment of neurosyphilis and reasons for renewed debate are briefly reviewed and discussed. Experience with 11 patients with neurosyphilis who were treated with different preparations of penicillin by different routes of administration is recorded. The concentration of penicillin was measured in the serum and cerebrospinal fluid in each case. Very high levels were attained by the intravenous administration of penicillin G, but in the follow-up period of 1 year this has not been shown to confer any advantage. The administration of procaine penicillin 1.2 million U intramuscularly daily for 20 days is as effective as a dosage schedule which requires admission to hospital for intravenous administration.

Nosocomial infections in a respiratory intensive care unit.

A total of 250 consecutive admissions to an open-plan respiratory ICU were analyzed prospectively to identify the incidence of secondary hospital-acquired infections and possible predisposing factors. Despite preventative measures and a restricted antibiotic policy, 23.6% of patients developed secondary infections. Patients admitted after multiple trauma were the only diagnostic category of patients who showed a significantly increased incidence of secondary infections. The length of hospitalization and number of patients who had intubations or tracheostomies was higher in the group with secondary infection; the causal relationship was difficult to establish. Patients who were not intubated or tracheostomized did not develop secondary infection. Prior administration of antibiotics did not appear to influence the incidence of secondary infection. There was a significant increase in secondary infections in patients with a higher therapeutic intervention scoring system score. The predominant pathogens cultured were highly resistant Gram-negative organisms, particularly Acinetobacter sp. and Pseudomonas sp. Staphylococcus aureus was the most common Gram-positive pathogen. The ICU course was probably prolonged by the complication of nosocomial infection, which may have contributed to the deaths.

Ceftriaxone therapy in adults with severe lower respiratory tract infections.

Ceftriaxone, a third-generation cephalosporin with a wide spectrum of antimicrobial activity and a long half-life of 8 hours permitting administration every 24 hours, was evaluated in 33 patients with severe lower respiratory tract infections. Twenty-nine patients showed a favourable clinical response and 2 failed to respond to therapy. In 2 patients the clinical response was impossible to assess. In 19 of the 23 patients in whom it was possible to assess bacteriological response, there was a favourable outcome. Serum ceftriaxone levels were well maintained above the minimal inhibitory concentrations of sensitive organisms for the entire dosage interval whether the drug was given by intramuscular or intravenous injection. There were no side-effects that could be attributed to ceftriaxone, which was highly effective in the immediate treatment of both community and nosocomial acquired severe lower respiratory tract infections.

Pyogenic liver abscess caused by Streptococcus milleri. Case reports.

In recent years Streptococcus milleri has emerged as an important cause of pyogenic liver abscess. Whether this represents a changing epidemiological pattern or merely reflects the more widespread application of routine anaerobic bacterial culture techniques is unclear. The isolation of Strept. milleri on culture of a blood specimen from a patient presenting with a pyrexial illness should alert the clinician to the possibility of an underlying liver abscess. Although it is isolated anaerobically this organism should not be mistaken for an obligate anaerobe, especially since it is resistant to metronidazole. Two cases of primary pyogenic liver abscess caused by this organism are reported.

Infectious complications after heart transplantation.

Infection has been the major cause of death and morbidity in patients undergoing cardiac transplantation at Groote Schuur Hospital. Twenty-two (55%) patients suffered at least one major episode of infection, which accounted for 10 (59%) of the deaths in the first year. The major site of origin of infection was the lung, though dissemination was not infrequent. Bacteria accounted for 22 (59%) infections; but viral, fungal and protozoal infections were not uncommon and in fact accounted for seven (64%) of the fatal infections. Several unusual causative microorganisms have been isolated in this group of immunocompromised subjects. There is a higher incidence of infection in patients over the age of 35 years and in patients who did not comply with instructions and advice.

Acute community-acquired pneumonias.

Of 81 adult patients with community-acquired pneumonia, bacterial infections were found in 37%, mycoplasma and viral infections in 21%, and tuberculosis in 6%; no pathogen could be identified in 46% of cases. More than one agent was identified in 12% of patients. Streptococcus pneumoniae, the most common pathogen, was found in 63%, Haemophilus influenzae in 26,7%, Staphylococcus aureus in 6,7%, and other Gram-negative organisms in 10% of patients with proven bacterial pneumonia. Most clinical and radiographic features were of little value in differentiating between different aetiological agents, but Gram-stained sputum gave a valuable early guide to therapy in 60% of cases of proven bacterial pneumonia. Blood culture was positive in 13,6% of cases. All the organisms conformed to their usual sensitivity patterns. Since Strept. pneumoniae is the predominant pathogen, penicillin should be the drug of choice in the immediate 'blind' treatment of community-acquired pneumonia.