Epidemiology of infection in ICUs

Novel and Rapid Diagnostics for Common Infections in the Critically Ill Patient

There are several novel platforms that enhance detection of pathogens that cause common infections in the intensive care unit. These platforms have a sample to answer time of a few hours, are often higher yield than culture, and have the potential to improve antibiotic stewardship.

Novel and Rapid Diagnostics for Common Infections in the Critically Ill Patient

There are several novel platforms that enhance detection of pathogens that cause common infections in the intensive care unit. These platforms have a sample to answer time of a few hours, are often higher yield than culture, and have the potential to improve antibiotic stewardship.

Diagnosing ventilator-associated pneumonia (VAP) in UK NHS ICUs: the perceived value and role of a novel optical technology

BACKGROUND

Diagnosing ventilator-associated pneumonia (VAP) in an intensive care unit (ICU) is a complex process. Our aim was to collect, evaluate and represent the information relating to current clinical practice for the diagnosis of VAP in UK NHS ICUs, and to explore the potential value and role of a novel diagnostic for VAP, which uses optical molecular alveoscopy to visualise the alveolar space.

METHODS

Qualitative study performing semi-structured interviews with clinical experts. Interviews were recorded, transcribed, and thematically analysed. A flow diagram of the VAP patient pathway was elicited and validated with the expert interviewees. Fourteen clinicians were interviewed from a range of UK NHS hospitals: 12 ICU consultants, 1 professor of respiratory medicine and 1 professor of critical care.

RESULTS

Five themes were identified, relating to [1] current practice for the diagnosis of VAP, [2] current clinical need in VAP diagnostics, [3] the potential value and role of the technology, [4] the barriers to adoption and [5] the evidence requirements for the technology, to help facilitate a successful adoption. These themes indicated that diagnosis of VAP is extremely difficult, as is the decision to stop antibiotic treatment. The analysis revealed that there is a clinical need for a diagnostic that provides an accurate and timely diagnosis of the causative pathogen, without the long delays associated with return of culture results, and which is not dangerous to the patient. It was determined that the technology would satisfy important aspects of this clinical need for diagnosing VAP (and pneumonia, more generally), but would require further evidence on safety and efficacy in the patient population to facilitate adoption.

CONCLUSIONS

Care pathway analysis performed in this study was deemed accurate and representative of current practice for diagnosing VAP in a UK ICU as determined by relevant clinical experts, and explored the value and role of a novel diagnostic, which uses optical technology, and could streamline the diagnostic pathway for VAP and other pneumonias.

Antibiotic resistance and sensitivity pattern of Metallo-β-Lactamase Producing Gram-Negative Bacilli in ventilator-associated pneumonia in the intensive care unit of a public medical school hospital in Bangladesh

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in intensive care units (ICU), accounting for 25% of all ICU infections. Antimicrobial resistance is increasing and becoming a significant health problem worldwide, increasing hospital length of stay, mortality and costs. Identifying antibiotic resistance patterns in VAP is important as this can cause outbreaks in ICUs. To date, there have been limited studies assessing this in Bangladesh. Consequently, the primary objective of this research was to study the species of bacterial growth and to determine the antibiotic resistance patterns of Metallo-β-Lactamase (MBL) producing gram-negative bacilli among ICU patients with VAP in a public medical school hospital, Bangladesh. In addition, identify the factors associated with a positive culture to provide future guidance.

METHOD

Cross-sectional study performed in the Chattogram Medical College Hospital, Bangladesh. Mueller Hinton agar plates were used for antibiotic sensitivity testing by the Kirby-Buer disc diffusion test.

RESULTS

Among 105 clinically suspected VAP cases, qualitative cultures were positive in 95 (90%) of them. The most common bacteria identified were Acinetobacter spp. (43.2%), Klebsiella spp. (20%) and Pseudomonas spp. (18.9%). A positive culture was not associated with patients' age or gender. Among 41 isolated Acinetobacter spp., 38 (92.7%) were resistant to gentamicin followed by 36 (87.8%) to ceftriaxone. Among 24 isolated Klebsiella spp., 22 (83.3%) were resistant to ceftriaxone. Among 18 isolated Pseudomonas spp., 16 (88.8%) were resistant to ciprofloxacin, and 13 (72.2%) were resistant to ceftriaxone. Among nine isolated E. coli, all were resistant to ceftriaxone and ciprofloxacin. All four Proteus spp. (100%) isolated were resistant to ciprofloxacin. Additionally, phenotype MBL producing was 65.22% and genotype was 45.65% among imipenem resistant pathogens. Imipenem resistant pathogens were sensitive to amoxyclav, amikacin¸ azithromycin, ceftazidime, ceftriaxone, colistin and gentamycin.

CONCLUSION

A positive culture was detected in 90% of VAP patients, but it was not associated with the patients' age and gender. The most common bacteria identified were Acinetobacter spp., Klebsiella spp. and Pseudomonas spp., where the majority of these were resistant to ceftriaxone. The results are being used to provide future guidance on the empiric management of VAP in this hospital.

Nosocomial Infection Agents of Şişli Hamidiye Etfal Training and Research Hospital: Comparison of 1995 and 2017 Data

Objectives:

Healthcare-associated infections (HCAI), which are important causes of mortality and morbidity, are high cost but preventable infections. This study aimed to determine hospital infections and isolates in Şişli Hamidiye Etfal Training and Hospital and to determine our local data. The changes in the distribution of the isolates in this process were evaluated by comparing the data of 1995 and today.

Methods:

Materials sent to the microbiology laboratory of our hospital in 1995 and 2017 from the patients hospitalized in the period between June 1-December 31 were evaluated concerning hospital infection. The standard manual methods were used in 1995, while in 2017, MALDI-TOF MS was used for identification and BD Phoenix automated system for antibiotic susceptibility.

Results:

In 1995, in total, 100 bacteria were isolated from pediatric and adult patients, of which 48 Pseudomonas aeruginosa (48/100), 37 Klebsiella spp (37/100). In 2017, Acinetobacter baumannii causing an important resistance problem was found to be increased in number. The main hospital infection causes were Acinetobacter baumannii (37/179), Klebsiella spp (41/179). In 2017, bacterial diversity was also increased.

Conclusion:

Isolated strains, as in the past, are gram-negative bacteria, Pseudomonas spp decreased in 2017, and Acinetobacter spp increased. The findings suggest that the automated systems used in microbiology laboratories may have a role in the detection of bacterial diversity.

Epidemiology and risk factors for nosocomial infection in the respiratory intensive care unit of a teaching hospital in China: A prospective surveillance during 2013 and 2015

BACKGROUND

To determine the epidemiology and risk factors for nosocomial infection (NI) in the Respiratory Intensive Care Unit (RICU) of a teaching hospital in Northwest China.

METHODS

An observational, prospective surveillance was conducted in the RICU from 2013 to 2015. The overall infection rate, distribution of infection sites, device-associated infections and pathogen in the RICU were investigated. Then, the logistic regression analysis was used to test the risk factors for RICU infection.

RESULTS

In this study, 102 out of 1347 patients experienced NI. Among them, 87 were device-associated infection. The overall prevalence of NI was 7.57% with varied rates from 7.19 to 7.73% over the 3 years. The lower respiratory tract (43.1%), urinary tract (26.5%) and bloodstream (20.6%) infections accounted for the majority of infections. The device-associated infection rates of urinary catheter, central catheter and ventilator were 9.8, 7.4 and 7.4 per 1000 days, respectively.The most frequently isolated pathogens were Staphylococcus aureus (20.9%), Klebsiella pneumoniae (16.4%) and Pseudomonas aeruginosa (10.7%). Multivariate analysis showed that the categories D or E of Average Severity of Illness Score (ASIS), length of stay (10-30, 30-60, ≥60 days), immunosuppressive therapy and ventilator use are the independent risk factors for RICU infection with an adjusted odds ratio (OR) of 1.65 (95% CI: 1.15~2.37), 5.22 (95% CI: 2.63~10.38)), 2.32 (95% CI: 1.19~4.65), 8.93 (95% CI: 3.17~21.23), 31.25 (95% CI: 11.80~63.65)) and 2.70 (95% CI: 1.33~5.35), respectively.

CONCLUSION

A relatively low and stable rate of NI was observed in our RICU through year 2013-2015. The ASIS-D、E, stay ≥10 days, immunosuppressive therapy and ventilator use are the independent risk factors for RICU infection.

Epidemiological study of prevalence, determinants, and outcomes of infections in medical ICU at a tertiary care hospital in India

OBJECTIVES

To determine the prevalence of infections, risk factors, and outcomes in a medical intensive care unit (ICU), we performed a hospital-based study.

MATERIALS AND METHODS

Consecutive patients were enrolled and details of risk factors and bacteriological data were obtained. Outcomes were death/transfer to palliative care or recovery. Statistical analyses were performed.

RESULTS

Four hundred and eighty-seven patients were admitted during the study period (age 55.6 ± 19 yr, men 68%). Diseases responsible were respiratory (37%), gastrointestinal/liver (22%), neurological (20%), renal (8%), and trauma (6%) related. Majority of admissions were direct (45%) or transfers from other hospitals (41%). Most important comorbidities were hypertension (41%), diabetes (31%), and chronic obstructive pulmonary disease (15%). Median APACHE-2 score was 13.0 (IQR 1-25). Antibiotics were administered in 98%. Bacteriological cultures were positive in 28% (n = 623). Respiratory infections were the most common (45.5%) followed by blood (23.3%) and urinary (16.1%). Gram-negative bacteria were common-Acinetobacter baumannii (20.9%), Klebsiella pneumoniae (19.7%), Escherichia coli (18.3%), and Pseudomonas aeruginosa (14.0%). There a high prevalence of resistance to common antibiotics. Patients with positive cultures were older, transferees (46 vs 37%, P = 0.07), with respiratory disease (48 vs. 33%, P = 0.003), with more than two comorbidities (33 vs 21%, P = 0.009), and higher APACHE-2 score (17.7 ± 8 vs. 13.3 ± 8, P = 0.07). Three hundred and fifty-two (72.3%) recovered, 68 (13.9%) died, and 67 (13.8%) were transferred to palliative care. Survival was associated with younger age, lower APACHE-2 score, negative cultures, and shorter duration in ICU (P < 0.05). Mortality was greater in patients with Acinetobacter (OR 2.36, 1.17-4.73), Klebsiella (OR 2.81, 1.33-5.92), Pseudomonas (OR 8.03, 2.83-22.76), or Enterobacter (OR 6.73, 1.29-35.12) infection.

CONCLUSIONS

There is high prevalence of infections in patients in a medical ICU in India. Gram-negative bacteria are the most prevalent and resistance to antibiotics is high. Risk factors are age, hospital transfers, APACHE-2 score, and multiple comorbidities.

Coagulase-negative Staphylococcus, catheter-related, bloodstream infections and their association with acute phase markers of inflammation in the intensive care unit: An observational study

OBJECTIVE

To examine the relationship between the isolation of coagulase-negative Staphylococcus in blood cultures and acute phase markers of inflammation.

METHODS

The present study was a prospective observational analysis conducted at three medical/surgical intensive care units (ICUs) involving adult patients with an expected ICU stay of more than 24 h duration.

RESULTS

Of the 598 patients enrolled, 573 developed suspected bloodstream infection and 434 (72.6%) had blood cultures sent 24 h after ICU admission; 142 were excluded due to positive cultures from other sites. Of the remaining 292 patients, 31 (10.7%) grew coagulase-negative Staphylococcus, 59 (20.2%) grew known pathogenic organisms and 202 (69.2%) did not grow any organisms in their blood cultures. Twenty-five patients without suspicion of infection served as the control group. Interleukin (IL)-6, procalcitonin (PCT) and C-reactive protein (CRP) levels were highest among the known pathogen group (IL-6 271.8 U/L, PCT 4.6 U/L and CRP 164 mg/L), were similar between the coagulase-negative Staphylococcus and negative culture groups (IL-6 67.0 U/L versus 61.4 U/L [P=1.00]; PCT 1.0 U/L versus 0.9 U/L [P=0.80]; and CRP 110 mg/L versus 103 mg/L [P=0.75]), and were lowest in the control group (IL-6 31.0 U/L, PCT 0.2 U/L and CRP 41.0 mg/L). In the coagulase-negative Staphylococcus group, patients who died by day 28 had increased inflammatory bio-marker levels compared with survivors, although the differences were not statistically significant.

CONCLUSIONS

Coagulase-negative Staphylococcus isolated from blood cultures were associated with lower levels of inflammation compared with bloodstream infections due to known pathogens and were comparable with levels in patients with negative cultures.

Assessment of risk factors related to healthcare-associated methicillin-resistant Staphylococcus aureus infection at patient admission to an intensive care unit in Japan

BACKGROUND

Healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) infection in intensive care unit (ICU) patients prolongs ICU stay and causes high mortality. Predicting HA-MRSA infection on admission can strengthen precautions against MRSA transmission. This study aimed to clarify the risk factors for HA-MRSA infection in an ICU from data obtained within 24 hours of patient ICU admission.

METHODS

We prospectively studied HA-MRSA infection in 474 consecutive patients admitted for more than 2 days to our medical, surgical, and trauma ICU in a tertiary referral hospital in Japan. Data obtained from patients within 24 hours of ICU admission on 11 prognostic variables possibly related to outcome were evaluated to predict infection risk in the early phase of ICU stay. Stepwise multivariate logistic regression analysis was used to identify independent risk factors for HA-MRSA infection.

RESULTS

Thirty patients (6.3%) had MRSA infection, and 444 patients (93.7%) were infection-free. Intubation, existence of open wound, treatment with antibiotics, and steroid administration, all occurring within 24 hours of ICU admission, were detected as independent prognostic indicators. Patients with intubation or open wound comprised 96.7% of MRSA-infected patients but only 57.4% of all patients admitted.

CONCLUSIONS

Four prognostic variables were found to be risk factors for HA-MRSA infection in ICU: intubation, open wound, treatment with antibiotics, and steroid administration, all occurring within 24 hours of ICU admission. Preemptive infection control in patients with these risk factors might effectively decrease HA-MRSA infection.

MRSA in a large German University Hospital: Male gender is a significant risk factor for MRSA acquisition

BACKGROUND

The continually rising number of hospital acquired infections and particularly MRSA (Methicillin-resistant Staphylococcus aureus) colonization poses a major challenge from both clinical and epidemiological perspectives. The assessment of risk factors is vital in determining the best prevention, diagnosis and treatment strategies.

MATERIALS AND METHODS

We analyzed 798 cases of MRSA in a large German University Hospital over a 7-year period. Data was collected retro- and prospectively including patient age, sex, type of ward and duration of inpatient stay. In addition we analyzed all cases on ICU with regards to cross infection and MRSA genotyping via DNA MicroArray Technology. The years 2004 to 2007 were analyzed with a specific focus on gender.

RESULTS

Male gender is significantly correlated with increased risk of MRSA acquisition (p<0.001), the predominant setting for MRSA is on ICU. 75% of the MRSA positive patients are over 50 years of age (average age 59.8 years). The inpatient time was 4.15 times higher in MRSA carriers compared with non-MRSA cases, however this was not significant. MRSA genotyping on ICU showed mainly the subtypes ST 5, ST 22, ST 228, however cross contamination with identical genotypes was only detected in a minority of cases (5 out of 22).

CONCLUSION

Unlike previous studies which show no or inconclusive evidence of gender as a risk factor, our data confirm that male gender is a significant risk factor for MRSA carrier status. Further research will be required to investigate the aetiology of these findings.

Data correction pre-processing for electronically stored blood culture results: implications on microbial spectrum and empiric antibiotic therapy

BACKGROUND

The outcome of patients with bacteraemia is influenced by the initial selection of adequate antimicrobial therapy. The objective of our study was to clarify the influence of different crude data correction methods on a) microbial spectrum and ranking of pathogens, and b) cumulative antimicrobial susceptibility pattern of blood culture isolates obtained from patients from intensive care units (ICUs) using a computer based tool, MONI.

METHODS

Analysis of 13 ICUs over a period of 7 years yielded 1427 microorganisms from positive results. Three different data correction methods were applied. Raw data method (RDM): Data without further correction, including all positive blood culture results. Duplicate-free method (DFM): Correction of raw data for consecutive patient's results yielding same microorganism with similar antibiogram within a two-week period. Contaminant-free method (CFM): Bacteraemia caused by possible contaminants was only assumed as true bloodstream infection, if an organism of the same species was isolated from > 2 sets of blood cultures within 5 days.

RESULTS

Our study demonstrates that different approaches towards raw data correction - none (RDM), duplicate-free (DFM), and a contaminant-free method (CFM) - show different results in analysis of positive blood cultures. Regarding the spectrum of microorganisms, RDM and DFM yielded almost similar results in ranking of microorganisms, whereas using the CFM resulted in a clinically and epidemiologically more plausible spectrum.

CONCLUSION

For possible skin contaminants, the proportion of microorganisms in terms of number of episodes is most influenced by the CFM, followed by the DFM. However, with exception of fusidic acid for gram-positive organisms, none of the evaluated correction methods would have changed advice for empiric therapy on the selected ICUs.

The acquisition and outcome of ICU-acquired Clostridium difficile infection in a single centre in the UK

BACKGROUND

The clinical course and outcome of Clostridium difficile infection (CDI) in the intensive care unit (ICU) setting have been reported in a small number of studies in the US and Canada. However, no such study has been reported in the UK. Therefore, we aimed to study the acquisition rate and outcome of ICU-acquired CDIs in our unit.

METHOD

Patient admissions to the ICU and nosocomial infection databases from April 2004 to April 2007 were reviewed to identify study groups, followed by retrospective case note review. Patients who acquired CDI prior to ICU admission were excluded.

RESULTS

Sixty-two patients (31 males) who acquired CDI during their ICU stays were included in our study. The acquisition rate of CDI ranged from 1.52 to 4.78% per year. The median APACHE II score was 18, and the median interval between ICU admission and acquisition of CDI was 7 days. The median ICU stay was 16 days. Of the 62 patients, 13 (20.97%) died in the ICU. Of the 49 patients who were discharged, 41 were discharged ultimately from the hospital. Thus, the overall mortality attributable to CDI acquired in the ICU was 33.87%, compared to the average baseline mortality of 29% in our unit. Univariate analysis showed that increasing age (p = 0.004), APACHE II score (p=0.007), and male gender (p = 0.05) were significantly associated with ICU mortality in patients who acquired CDI in the ICU. Multivariate analysis showed that only increasing age (p = 0.031; OR 1.141, CI 1.013-1.287) was significantly associated with higher ICU mortality.

CONCLUSION

Patients admitted to the ICU have a moderate risk of acquiring CDI. There is a small increase in mortality observed in patients who acquired CDI in the ICU. Increasing age is an independent predictor associated with mortality.

Impact of appropriateness of initial antibiotic therapy on outcome of postoperative pneumonia

BACKGROUND

Although delay in the administration of appropriate antibiotic treatment for ventilator-associated or community-acquired pneumonia is associated with increased hospital mortality, impact of appropriateness of initial antibiotic therapy on outcome of postoperative pneumonia has been poorly investigated.

MATERIALS AND METHODS

Of 7,275 patients who had undergone intraabdominal surgery under general anesthesia between January 1998 and December 2005, we compiled a list of 101 patients with microbiologically confirmed postoperative pneumonia. We analyzed the influence of the appropriateness of initial antibiotic therapy on outcome of postoperative pneumonia using logistic regression analysis.

RESULTS

Among the patients with postoperative pneumonia, about a half received inadequate initial antimicrobial therapy. As well as the presence of concomitant intraabdominal abscess [odds ratio (OR) = 28.83), prolonged duration of anesthesia at surgery (OR = 22.41), and the isolation of methicillin-resistant Staphylococcus aureus (OR = 8.86), inadequate initial antibiotic therapy was a determinant of death from postoperative pneumonia (OR = 16.75).

CONCLUSION

The outcomes of patients with postoperative pneumonia could be improved by avoiding concomitant intraabdominal abscess, reducing surgical insult, and administering appropriate antimicrobial agents.

Use of Broad-Spectrum Antimicrobials for the Treatment of Pneumonia in Seriously Ill Patients: Maximizing Clinical Outcomes and Minimizing Selection of Resistant Organisms

Among various risk factors for death among critically ill patients with serious infection, inappropriate antimicrobial therapy is an important factor that clinicians can modify directly. The presence of multidrug-resistant bacteria is the primary reason that patients with ventilator-associated pneumonia receive inappropriate antimicrobial therapy. Empirical antimicrobial therapy for ventilator-associated pneumonia should be initiated promptly and should have a broad spectrum that covers all potential antimicrobial-resistant pathogens. Delaying the start of therapy or modifying an inappropriate antimicrobial regimen does not improve outcome, probably because the change comes too late to redirect the course of illness. Timely empirical therapy with highly effective agents that are rapidly bactericidal could minimize the emergence of resistance. Broad-spectrum therapy should be streamlined (i.e., de-escalated), as appropriate, on the basis of microbiological data and clinical response. Switching to narrower-spectrum therapy that is directed by culture results may minimize the emergence of resistance. For some patients, clinical response will allow a shortening of the duration of antimicrobial therapy.

Contribution of clonal dissemination and selection of mutants during therapy to Pseudomonas aeruginosa antimicrobial resistance in an intensive care unit setting

Rates of antibiotic resistance in Pseudomonas aeruginosa isolates from intensive care unit (ICU) patients are expected to be dependent on the selection of resistance mutations during therapy, the availability of exogenous resistance determinants and their dissemination potential, and the efficiency of transmission of the resistant strains. The relative contributions of these three factors were studied in an ICU with no apparent outbreak in 216 sequential P. aeruginosa isolates recovered from 102 patients between September 2002 and November 2003. Analysis of pulsed-field gel electrophoresis patterns revealed the presence of 82 different clones. Thus, the dissemination of particular resistant clones had a minimal effect on the relatively high overall resistance frequencies found for imipenem (32%), cefepime (25%), ceftazidime (24%), meropenem (22%), ciprofloxacin (18%) and tobramycin (2%). Rates of primary resistance were relatively low, and resistance development during treatment (secondary resistance) was the main factor contributing to the overall high resistance rates. In ICU settings with a low prevalence of epidemic resistant strains, the main strategy for resistance control should focus on the design of targeted regimens to avoid the development of resistance.

Surveillance and infection control in an intensive care unit

OBJECTIVE

To evaluate the effect of an infection control program on the incidence of hospital-acquired infection (HAI) and associated mortality.

DESIGN

Prospective study.

SETTING

A 2000-bed, university-affiliated hospital in Italy.

PATIENTS

All patients admitted to the general intensive care unit (ICU) for more than 48 hours between January 2000 and December 2001.

METHODS

The infection control team (ICT) collected data on the following from all patients: demographics, origin, diagnosis, severity score, underlying diseases, invasive procedures, HAI, isolated microorganisms, and antibiotic susceptibility.

INTERVENTIONS

Regular ICT surveillance meetings were held with ICU personnel. Criteria for invasive procedures, particularly central venous catheters (CVCs), were modified. ICU care was restricted to a team of specialist physicians and nurses and ICU antimicrobial therapy policies were modified.

RESULTS

Five hundred thirty-seven patients were included in the study (279 during 2000 and 258 in 2001). Between 2000 and 2001, CVC exposure (82.8% vs 71.3%; P < .05) and mechanical ventilation duration (11.2 vs 9.6 days) decreased. The HAI rate decreased from 28.7% in 2000 to 21.3% in 2001 (P < .05). The crude mortality rate decreased from 41.2% in 2000 to 32.9% in 2001 (P < .05). The most commonly isolated microorganisms were nonfermentative gram-negative organisms and staphylococci (particularly MRSA). Mortality was associated with infection (relative risk, 2.11; 95% confidence interval, 1.72-2.59; P < .05).

CONCLUSION

Routine surveillance for HAI, coupled with new measures to prevent infections and a revised policy for antimicrobial therapy, was associated with a reduction in ICU HAls and mortality.

The spectrum of practice in the diagnosis and management of pneumonia in patients requiring mechanical ventilation. Australian and New Zealand practice in intensive care (ANZPIC II)

This study of ventilated patients investigated current clinical practice in 476 episodes of pneumonia (48% community-acquired pneumonia, 24% hospital-acquired pneumonia, 28% ventilator-associated pneumonia) using a prospective survey in 14 intensive care units (ICUs) within Australia and New Zealand. Diagnostic methods and confidence, disease severity, microbiology and antibiotic use were assessed. All pneumonia types had similar mortality (community-acquired pneumonia 33%, hospital-acquired pneumonia 37% and ventilator-associated pneumonia 24%, P=0.15) with no inter-hospital differences (P=0.08-0.91). Bronchoscopy was performed in 26%, its use predicted by admission hospital (one tertiary: OR 9.98, CI 95% 5.11-19.49, P< 0.001; one regional: OR 6.29, CI 95% 3.24-12.20, P<0.001), clinical signs of consolidation (OR 3.72, CI 95% 2.09-6.62, P<0.001) and diagnostic confidence (OR 2.19, CI 95% 1.29-3.72, P=0.004). Bronchoscopy did not predict outcome (P=0.11) or appropriate antibiotic selection (P=0.69). Inappropriate antibiotic prescription was similar for all pneumonia types (11-13%, P=0.12) and hospitals (0-16%, P=0.25). Blood cultures were taken in 51% of cases. For community-acquired pneumonia, 70% received a third generation cephalosporin and 65% a macrolide. Third generation cephalosporins were less frequently used for mild infections (OR 0.38, CI 95% 0.16-0.90, P=0.03), hospital-acquired pneumonia (OR 0.40, CI 95% 0.23-0.72, P<0.01), ventilator-associated pneumonia (OR 0.04, CI 95% 0.02-0.13, P<0.001), suspected aspiration (OR 0.20, CI 95% 0.04-0.92, P=0.04), in one regional (OR 0.26, CI95% 0.07-0.97, P=0.05) and one tertiary hospital (OR 0.14, CI 95% 0.03-0. 73, P=0.02) but were more commonly used in older patients (OR 1.02, CI 95% 1.01-1.03, P=0.01). There is practice variability in bronchoscopy and antibiotic use for pneumonia in Australian and New Zealand ICUs without significant impact on patient outcome, as the prevalence of inappropriate antibiotic prescription is low. There are opportunities for improving microbiological diagnostic work-up for isolation of aetiological pathogens.

Antibiotic-treated infections in intensive care patients in the UK

The purpose of this audit was to study reasons for starting antibiotic therapy, duration of antibiotic treatment, reasons for changing antibiotics and the agreement between clinical suspicion and microbiological results in intensive care practice. We conducted a multicentre observational audit of 316 patients. Data on demographic details, site, treatment and nature of infection were collected. The median duration of antibiotic therapy was 7 days. Infections were community-acquired in 160 patients (55%). Antibiotics were started on clinical suspicion of infection in 237 patients (75%). Pulmonary infections were the most common, representing 52% of all proven infections. Gram-negative organisms were the most common cause of proven infections (n = 90 (50%)). The antibiotic spectrum was narrowed in light of microbiology results in 78 patients (43%) and changed due to antibiotic resistance in 38 patients (21%). We conclude that the mean duration of treatment contrasts with existing published guidelines, highlighting the need for further studies on duration and efficacy of treatment in intensive care.

Putting copper into action: copper-impregnated products with potent biocidal activities

Copper ions, either alone or in copper complexes, have been used for centuries to disinfect liquids, solids, and human tissue. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide, and antibacterial and antifouling agent. Copper also displays potent antiviral activity. We hypothesized that introducing copper into clothing, bedding, and other articles would provide them with biocidal properties. A durable platform technology has been developed that introduces copper into cotton fibers, latex, and other polymeric materials. This study demonstrates the broad-spectrum antimicrobial (antibacterial, antiviral, antifungal) and antimite activities of copper-impregnated fibers and polyester products. This technology enabled the production of antiviral gloves and filters (which deactivate HIV-1 and other viruses), antibacterial self-sterilizing fabrics (which kill antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci), antifungal socks (which alleviate symptoms of athlete's foot), and anti-dust mite mattress covers (which reduce mite-related allergies). These products did not have skin-sensitizing properties, as determined by guine pig maximization and rabbit skin irritation tests. Our study demonstrates the potential use of copper in new applications. These applications address medical issues of the greatest importance, such as viral transmissions; nosocomial, or healthcare-associated, infections; and the spread of antibiotic-resistant bacteria.

Nosocomial Pneumonia

Nosocomial pneumonia (NP) is defined as pneumonia that develops within 48 hours or more of hospital admission and which was not developing at the time of admission. Nosocomial pneumonia, also known as hospital-acquired pneumonia (HAP), is the second most common hospital infection, while ventilator-associated pneumonia represents the most common intensive care unit (ICU) infection. Nosocomial pneumonia significantly contributes to morbidity, mortality, and escalating healthcare costs because of increases in antibiotic prescription and administration, length of ICU stay, and length of hospital stay. Aspiration and colonization of the upper respiratory tract seem to be the major pathogenetic mechanisms for the development of NP, either in intubated or spontaneously breathing patients. The microbiology of NP depends on the timing of onset. In early-onset NP, the responsible pathogens are generally endogenous community-acquired pathogens. In late-onset NP, the responsible microbes include potentially multi-drug-resistant nosocomial organisms residing in oropharyngeal or gastric contents. Important risk factors for development of NP include coma, intubation, prolonged mechanical ventilation, repeated intubations, supine positioning, and long-term antibiotic use. The most significant preventive measures include routine hand washing and avoidance of (1) the supine position, (2) inappropriate antibiotics, and (3) overuse of H2-antagonists for stress ulcer prophylaxis. Accurate diagnosis of NP is difficult and controversial, warranting consideration for the application of invasive quantitative culture techniques over tracheal aspirates. Empiric antibiotic treatment should be prompt, starting on clinical suspicion, and based on local ICU pathogen epidemiology and antibiotic resistance patterns and on a deescalating antibiotic strategy. Innovative antibiotic strategies, such as antibiotic rotation, to help prevent the emergence of multi-drug-resistant pathogens and improve survival should be considered.

Gastric tonometry and monitoring gastrointestinal perfusion: using research to support nursing practice

The principles and physiological underpinnings of gastric tonometry are reviewed. Tonometric variables, including the PtCO2, pHi and CO2 gap, are described and critiqued as measurements of gastrointestinal perfusion. Increases in gastrointestinal CO2 unrelated to gastrointestinal hypoperfusion are discussed within different clinical contexts. The technical limitations of gastric tonometry, including procedural errors and PtCO2 measurement are discussed in relation to the accuracy of tonometric measurements. Tonometric measurement using semi-continuous air tonometry is introduced as a strategy to minimize technical limitations.

Early diagnosis of candidiasis in non-neutropenic critically ill patients

OBJECTIVE

To determine a method for the early diagnosis of candidiasis in non-neutropenic critically ill patients in order to reduce mortality.

METHODS

A prospective study in non-neutropenic critically patients in whom Candida spp. were detected, was made in an intensive care unit (ICU) during an 8-year period from 3389 patients admitted. A diagnostic and therapeutic protocol was designed. Invasive candidiasis was defined according to dissemination and multifocality.

RESULTS

Candida spp. were found in 145 cases (4.3%): 120 (83%) were considered as invasive candidiasis and 25 as colonisation (17%). The hospital mortality was 46% (67/145). A post-mortem study was carried out in 54% (36/67) of hospital deaths. Candida albicans was the most frequently isolated species (87%), followed by Candida glabrata (18%). There were 24 candidemias and three cases of endophtalmitis. Digestive and respiratory samples and non-C. albicans yeasts were risk factors for invasive candidiasis. The mortality rate was related statistically to invasive candidiasis and inversely to the appropriate antifungal treatment.

CONCLUSIONS

Invasive candidiasis is related to digestive and respiratory samples and to the presence of non-C. albicans species. A simpler definition of invasive candidiasis in non-neutropenic critically ill patients will permit more rapid and accurate specific antifungal therapy.

Nosocomial pneumonia: the importance of a de-escalating strategy for antibiotic treatment of pneumonia in the ICU

Nosocomial pneumonia is the second most frequent nosocomial infection and represents the leading cause of death from infections that are acquired in the hospital. In the last decade, a large body of data has accumulated that points to the substantial impact of inadequate antibiotic treatment as a major risk factor for infection-attributed mortality in ventilator-associated pneumonia (VAP) patients. In most instances, high-risk pathogens (eg, highly resistant Gram-negative bacilli, such as Pseudomonas aeruginosa and Acinetobacter spp, as well as methicillin-resistant staphylococci) are the predominant microorganisms causing excess mortality. Among various risk factors for mortality from VAP, which include the severity of the underlying disease and the degree of functional physiologic impairment caused by the pulmonary infectious process, only inappropriate antibiotic therapy is directly amenable to modification by clinicians. Secondary modifications of an initially failing antibiotic regimen do not substantially improve the outcome for these critically ill patients. Therefore, the best approach for reducing infection-related mortality seems to be the initial institution of an adequate and broad-spectrum antibiotic regimen in severely ill patients, which should be modified in a de-escalating strategy when the results from microbiologic testing become available. To circumvent the inherent danger of the emergence of resistance in ICU patients, additional measures have to be implemented and tested in clinical trials to reduce antibiotic consumption, shorten the duration of antibiotic treatment, and reduce the selection pressure on the ICU flora. This latter goal could be met by new antibiotic strategies including scheduled changes of recommended empiric antibiotic regimens at fixed intervals on a rotating basis.

Nurses' knowledge and attitudes about antibiotic therapy in critical care

PURPOSE

To assess critical care nurses' knowledge about antibiotic use in critical care settings, and attitudes concerning the role of the nurse in monitoring response to and appropriate use of antibiotic therapy.

METHOD

90 critical care nurses from 6 adult critical care units at a 780-bed academic, health sciences centre, completed an investigator-developed survey about their knowledge of antibiotic use and their attitudes concerning the role of the nurse.

RESULTS

The majority of respondents worked full time (83%) and were BSN (Bachelor of Science in Nursing) prepared (62%), with an average of 9 years' nursing experience and 7 years' experience in intensive care. Using a 100-mm visual analog scale, mean scores on knowledge and comfort with: (1) interpreting culture and sensitivity; (2) white blood cell (WBC) data; and (3) discussing results and therapy with physicians were all less than 50 mm. However, the mean score for nurses' belief of responsibility related to this collaborative role was 76. A knowledge quiz of lab interpretation and antibiotic therapy revealed a mean score of 53.8%. Beliefs about roles were correlated with comfort in discussing therapies with physicians rather than with knowledge. Although nurses value the collaborative surveillance role, they may lack the knowledge and confidence to enact it.

Enterococcal infections in a Greek intensive care unit: a 5-y study

In this study we determined the incidence, resistance pattern, and mortality rate associated with infection caused by Enterococcus faecalis and Enterococcus faecium among patients in a multidisciplinary intensive care unit (ICU). A total of 111 patients with E. faecalis and 60 with E. faecium infections were identified during a 5-y period (1992-96). We observed an increase in the incidence of enterococcal infections (from 5.46 to 8.46 per 1000 patients-days, p = 0.0112), due mainly to the increased incidence of E. faecium (from 0.45 to 4.06 per 1000 patients-days, p = 0.002). Blood was the most common site of enterococcus isolation. E. faecium was more resistant to antibiotics than E. faecalis, but no vancomycin resistant enterococcus was isolated. Patients with E. faecium infection had a significantly higher mortality than patients with E. faecalis infection (66% vs. 41.5%, p = 0.0035 for infection from any site and 85.7 vs. 47.7%, p = 0.012 for bacteremic patients). r 4n- D I .- .- - .. . .

Risk assessment and standardized nosocomial infection rate in critically ill children

OBJECTIVES

To develop and validate a pediatric nosocomial infection risk (PNIR) assessment model, and to compare the daily trends in risk factors between patients with nosocomial infection (cases) and without nosocomial infection (controls) in the pediatric intensive care unit (ICU).

DESIGN

Prospective cohort.

SETTING

A 16-bed pediatric ICU in an urban, university-affiliated, multidisciplinary, regional referral center.

PATIENTS

Patients available for study included consecutive admissions to the unit between May 1, 1992, and April 30, 1993, and between May 9, 1995, and December 11, 1995. Patients from both data collection periods were pooled and randomly divided into training (70%) and validation (30%) samples.

MEASUREMENTS AND MAIN RESULTS

In the logistic regression analysis using admission day data, three factors were shown to remain as independent risk factors. Invasive device use, parenteral nutrition, and the interaction between severity of illness-modified Pediatric Risk of Mortality III-24 score and postoperative care were associated with 2, 6, and 1.5 times the risk of developing nosocomial infection, respectively. This PNIR model performed well in both the training and validation samples as indicated by the goodness-of-fit test, which evaluated standardized nosocomial infection rates (observed vs. predicted nosocomial infection rates). The internal validity of the PNIR model was good. In trend analysis, severity of illness and invasive device use appear to have similar trend patterns, during the first week of pediatric ICU stay. There was no difference in any of these risk factors between cases and controls after 7 days of pediatric ICU stay.

CONCLUSIONS

The PNIR assessment model incorporates intrinsic factors, such as patient severity of illness, and extrinsic factors contributing to the development of nosocomial infection in this high-risk population. The methodology using intrinsic and extrinsic factors to adjust for nosocomial infections should be taken into consideration when evaluating interhospital comparison of nosocomial infection rates, quality assessment, intervention strategies, and use of treatment modalities.

Rational empiric antibiotic prescription in the ICU

The prescribing of antibiotics in the ICU is usually empiric, given the critical nature of the conditions of patients hospitalized there. Appropriate antibiotic utilization in this setting is crucial not only in ensuring an optimal outcome, but in curtailing the emergence of resistance and containing costs. We propose that research in the ICUs is vitally important in guiding antibiotic prescription practices and, therefore, the achievement of above-stated goals. There is wide institutional diversity in the relative prevalence of predominant pathogens and their antimicrobial susceptibilities, and within individual ICUs there exist unique patient populations with varying risks for and susceptibilities to infections and specific pathogens. Appropriate antibiotic prescription practices should be formulated based on surveillance studies and research at individual ICUs; these goals can be accomplished utilizing existing resources.

Nosocomial endocarditis in the intensive care unit: an analysis of 22 cases

OBJECTIVES

To review the intensive care unit experience of patients with admitted or acquired nosocomial endocarditis (NE) defined according to the Duke criteria.

DESIGN

Prospective, cohort study.

SETTING

University teaching hospital.

PATIENTS

We reviewed the records of 22 patients documented with NE during a 6-yr period from 1992 to 1997.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Twenty-two patients (9 women/13 men) aged 38-83 yrs (mean 65+/-9 yrs) had a NE (prevalence of 5 per 1,000 admissions). For six patients, NE was the reason for the admission to the intensive care unit. For 17 patients, the time elapsed between admission and diagnosis of NE was 39+/-25 days. Sixteen patients were predisposed to infection and seven had underlying heart conditions that put them at risk for acute endocarditis: three prosthetic valves, two valvular diseases, and two cardiac pacemakers. In 21 cases (one unknown portal of entry), NE was the consequence of bacteremia related to a medical or surgical procedure: 11 intravascular devices, eight surgical wounds, one tracheal procedure, and one leg ulceration. The bacteriologic agents detected in blood cultures were: staphylococci (n = 17), Streptococcus (n = 2), Pseudomonas aeruginosa (n = 2), and Candida (n = 2). Fourteen patients underwent echocardiography according to cardiac signs (cardiac failure, new cardiac murmur, or embolic event). For the eight remainders, echocardiography was performed systematically because of fever and positive blood cultures. The lesions detected by 21 transthoracic and 17 transesophageal echocardiographs were the following: vegetations (n = 19), myocardial abscesses (n = 5), and valvular perforation (n = 1). On 16 surgical indications, only five patients underwent surgery because the others were in too poor of a condition. The overall mortality was 68% (n = 15) and was directly associated with NE in 36% of cases (n = 8). Seven patients (28%) were discharged 34 days after the diagnosis of endocarditis.

CONCLUSIONS

NE is a frequent nosocomial infection that occurs late during hospitalization. Persistent fever with positive blood cultures is sufficient symptomology to promptly perform an echocardiogram. The poor prognosis is related to the poor condition of those patients who cannot be referred for surgical treatment.

European survey of glycopeptide susceptibility in Staphylococcus spp

OBJECTIVE: To reassess the relative potencies of teicoplanin and vancomycin following several years of clinical usage. METHODS: The glycopeptide susceptibilities of clinical isolates of staphylococci collected from 70 hospitals in 1995 were determined using NCCLS (National Committee for Clinical Laboratory Standards) methods. RESULTS: In total, 2885 isolates of Staphylococcus aureus and 1480 isolates of coagulase-negative staphylococci were collected. S. aureus was significantly less susceptible to vancomycin (MIC50 1 mg/L) than teicoplanin (MIC50 0.5 mg/L), but the reverse was the case for S. haemolyticus and S. epidermidis. No S. aureus isolate was resistant (>/=32 mg/L) to either glycopeptide, but nine isolates of coagulase-negative staphylococci had an MIC of teicoplanin of 32 mg/L. Respiratory isolates of S. aureus were less susceptible to glycopeptides than those from other sites. Staphylococci from Belgium and Italy were less susceptible to teicoplanin than isolates from other countries. CONCLUSIONS: This European survey shows that in 10 years of clinical use there have been no major changes in the susceptibility of staphylococci to the glycopeptides.

Preventing central venous catheter-related infection in a surgical intensive-care unit

The cumulative effect of five measures (introduction of hand disinfection with alcohol, a new type of dressing, a one-bag system for parenteral nutrition, a new intravenous connection device, and surveillance by an infection control practitioner) on central venous catheter colonization and bacteremia was studied. Colonization was significantly reduced (P<.025); the decrease in bacteremia was not statistically significant.

Implementation of an interactive computer-assisted infection monitoring program at the bedside

A new computer-assisted infection monitoring (CAI) software program has been developed for use in an intensive-care unit (ICU). By means of an interactive dialogue with physicians at the bedside, infection diagnoses and therapeutic decisions were recorded prospectively during a 3-month test period. By linking epidemiological data with information about therapeutic decisions, CAI could assess the quality of the therapeutic decisions. Antibiotics chosen empirically before the availability of any culture results, matched the antibiotic susceptibility patterns of the subsequently identified pathogens in 74% of the cases. Therapy chosen in collaboration with the computer after the pathogen was known, but before sensitivity results were available, corresponded with the eventual antibiograms of the microorganisms in 90% of the cases. Data analysis by CAI allowed us to assess critically the diagnostic and therapeutic habits in our ICU. Using the query-by-example method, CAI automatically calculated device-associated infection rates.

Nosocomial infections in medical intensive care units in the United States. National Nosocomial Infections Surveillance System

OBJECTIVE

To describe the epidemiology of nosocomial infections in medical intensive care units (ICUs) in the United States.

DESIGN

Analysis of ICU surveillance data collected through the National Nosocomial Infections Surveillance (NNIS) System between 1992 and 1997.

SETTING

Medical ICUs in the United States.

PATIENTS

A total of 181,993 patients.

MEASUREMENTS AND MAIN RESULTS

Nosocomial infections were analyzed by infection site and pathogen distribution. Urinary tract infections were most frequent (31%), followed by pneumonia (27%) and primary bloodstream infections (19%). Eighty-seven percent of primary bloodstream infections were associated with central lines, 86% of nosocomial pneumonia was associated with mechanical ventilation, and 95% of urinary tract infections were associated with urinary catheters. Coagulase-negative staphylococci (36%) were the most common bloodstream infection isolates, followed by enterococci (16%) and Staphylococcus aureus (13%). Twelve percent of bloodstream isolates were fungi. The most frequent isolates from pneumonia were Gram-negative aerobic organisms (64%). Pseudomonas aeruginosa (21%) was the most frequently isolated of these. S. aureus (20%) was isolated with similar frequency. Candida albicans was the most common single pathogen isolated from urine and made up just over half of the fungal isolates. Fungal urinary infections were associated with asymptomatic funguria rather than symptomatic urinary tract infections (p < .0001). Certain pathogens were associated with device use: coagulase-negative staphylococci with central lines, P. aeruginosa and Acinetobacter species with ventilators, and fungal infections with urinary catheters. Patient nosocomial infection rates for the major sites correlated strongly with device use. Device exposure was controlled for by calculating device-associated infection rates for bloodstream infections, pneumonia, and urinary tract infections by dividing the number of device-associated infections by the number of days of device use. There was no association between these device-associated infection rates and number of hospital beds, number of ICU beds, or length of stay. There is a considerable variation within the distribution of each of these infection rates.

CONCLUSIONS

The distribution of sites of infection in medical ICUs differed from that previously reported in NNIS ICU surveillance studies, largely as a result of anticipated low rates of surgical site infections. Primary bloodstream infections, pneumonia, and urinary tract infections associated with invasive devices made up the great majority of nosocomial infections. Coagulase-negative staphylococci were more frequently associated with primary bloodstream infections than reported from NNIS ICUs of all types in the 1980s, and enterococci were a more frequent isolate from bloodstream infections than S. aureus. Fungal urinary tract infections, often asymptomatic and associated with catheter use, were considerably more frequent than previously reported. Invasive device-associated infections were associated with specific pathogens. Although device-associated site-specific infection rates are currently our most useful rates for performing comparisons between ICUs, the considerable variation in these rates between ICUs indicates the need for further risk adjustment.

European Glycopeptide Susceptibility Survey of gram-positive bacteria for 1995. European Glycopeptide Resistance Survey Study Group

In the European Glycopeptide Susceptibility Survey 7078 Gram-positive isolates collected in 1995 from 70 centers in 9 countries of Western Europe were examined, using a standardized, quantitative susceptibility testing method. Of the 7078 isolates, 6824 (96.4%) were tested by the national coordinating centers. Teicoplanin (mode MIC 0.5 microgram/mL) was generally twice as active as vancomycin (mode MIC 1 microgram/mL) against Staphylococcus aureus (n = 2852). All isolates were susceptible to vancomycin (MIC < or = 4 micrograms/mL) and all but four to teicoplanin (MIC < or = 8 micrograms/mL); these four isolates were of intermediate susceptibility (MIC 16 micrograms/mL). With coagulase-negative staphylococci (n = 1444), the distribution of MIC of teicoplanin was wider than for vancomycin. Two and two-tenths percent of coagulase-negative staphylococci excluding Staphylococcus haemolyticus required 16 micrograms/mL teicoplanin for inhibition (intermediate) and 0.4% > or = 32 micrograms/mL (resistant). Among isolates of S. haemolyticus, 4.4% were of intermediate susceptibility (MIC 16 micrograms/mL) and 3.3% were resistant (MIC > or = 32 micrograms/mL) to teicoplanin. However, this species represented only 6.3% of the isolates of coagulase-negative Staphylococcus spp. Generally, teicoplanin (mode MIC < or = 0.12 microgram/mL) was four to eight times more active than vancomycin (mode MIC < or = 0.5 microgram/mL) against the 770 streptococcal isolates. Glycopeptide-susceptible Enterococcus spp. (n = 1695) were generally four times more susceptible to teicoplanin (mode MIC 0.25 microgram/mL) than to vancomycin (mode MIC 1 microgram/mL). Combined vancomycin and teicoplanin (VanA phenotype) resistance was observed more frequently (9.3%) in isolates of Enterococcus faecium than in Enterococcus faecalis (0.8%). Four isolates of unspeciated enterococci (1.4%) also expressed this resistance phenotype. Four isolates of E. faecium and four of E. faecalis expressed the VanB-type (low-level, vancomycin only) resistance. Spain was the only country not to submit resistant E. faecium strains while resistant E. faecalis isolates came only from Spain and Italy.

Bacteraemia in the adult intensive care unit of a teaching hospital in Nottingham, UK, 1985-1996

Bacteraemia is an important cause of morbidity and mortality in the intensive care unit. In this study the distribution of organisms causing bacteraemic episodes in patients in the adult intensive care unit of a large teaching hospital was determined. Particular emphasis was placed on the type of organisms isolated from community- and hospital-acquired bacteraemia, the suspected source of infection, the possible risk factors associated with bacteraemia, and outcome. The incidence of bacteraemia and fungaemia increased from 17.7 per 1000 admissions in 1985 to 80.3 in 1996. A total of 315 episodes of bacteraemia and fungaemia were documented over a 12-year period, of which 18% were considered community-acquired and 82% hospital-acquired. Gram-positive and gram-negative bacteria accounted for 46.9% and 31.5% of the episodes, respectively. Polymicrobial infection accounted for 17.8% and fungi for 3.8% of the episodes. Staphylococcus aureus (22.5%), Staphylococcus epidermidis (7.6%), and Streptococcus pneumoniae (7.9%) were the predominant gram-positive bacteria implicated, whereas Escherichia coli (6%), Enterobacter cloacae (7%), Klebsiella aerogenes (3.8%), Pseudomonas aeruginosa (5.1%), and Acinetobacter spp. (3.8%) were the predominant gram-negative bacteria isolated. The two most common sources of infection were the respiratory tract (39.7%) and an intravascular line (24.5%), but in 8.9% of episodes the focus of infection remained unknown. Bacteraemic patients stayed in the unit for a longer period (12 days) than did non-bacteraemic patients (3 days). The overall mortality related to bacteraemia and candidaemia was 44.4%. Surveillance of bacteraemia in the intensive care unit is important in detecting major changes in aetiology, e.g., the increasing incidence of gram-positive bacteraemia, the emergence of methicillin-resistant Staphylococcus aureus in 1995, and the emergence of Enterobacter cloacae. It is of value in determining empirical antimicrobial therapy to treat presumed infection pending a microbiological diagnosis and in directing the development of guidelines for infection prevention, e.g., guidelines for central venous catheter care.

Reference values of gastric intramucosal pH in children

To determine the reference values of gastric intramucosal pH (pHi) by tonometry in paediatric patients, we studied 17 children (nine males, eight females) with no systemic or gastrointestinal disease, aged six months to 12 years undergoing minor reconstructive surgery. Following anaesthetic induction a sigmoid tonometry catheter was inserted (Tonometrics, Inc.) into the stomach of the patients under direct vision. All children were normoventilated and were haemodynamically stable. After an equilibration period of 30 min, gastric pHi was calculated by applying the Henderson-Hasselbalch equation on the PCO2 obtained with the tonometer and the bicarbonate from the arterial blood gas analysis. The mean gastric pHi in our patients was 7.35 +/- 0.06 (SD). The normal pHi in the general population is estimated to be 7.31-7.40, with a confidence interval of 99%. No correlation was found between pHi and arterial pH, bicarbonate or base excess. Under conditions of normal ventilation and haemodynamic stability, healthy children during general anaesthesia have gastric intramucosal values similar to those of adults.

Risks and routes for ventilator-associated pneumonia with Pseudomonas aeruginosa

In a prospective study, we screened specimens from 190 mechanically ventilated patients hospitalized in a surgical intensive care unit, and from the environment to assess risks and routes of colonization/infection. Specimens from various sites were collected on admission and once a week throughout each patient's stay. All P. aeruginosa isolates were typed by determination of DNA patterns. Data were collected from patients to identify risk factors. In vitro production of exoenzymes of different strains were compared. Forty-four patients were colonized with P. aeruginosa on the bronchopulmonary tract and 13 suffered from pneumonia. The 7-d and 14-d Kaplan-Meier rates of colonization were 2.21 and 7.03%. Twenty-one patterns of bronchopulmonary tract isolates were isolated from single patients and 10 from several patients. The lower airway was often the first site of colonization. The contribution of environment to patient colonization appeared to be small. The length of hospitalization, the previous use of third-generation cephalosporins less effective against P. aeruginosa, and chronic obstructive pulmonary disease were the most significant predictors of colonization/infection. The in vitro exoprotein production was not correlated with the presence of pneumonia. Our study may be useful in identifying which patients in the mechanically ventilated population are at greater risk of P. aeruginosa pneumonia.

A closer look at vancomycin, teicoplanin, and antimicrobial resistance

The worldwide increase in the incidence of resistant Gram-positive infections has renewed interest in the glycopeptide class of antimicrobial agents. Two glycopeptides are available in many parts of the world--vancomycin and teicoplanin. These two agents appear to differ in several respects, including: potential for selecting microbial resistance, dosing convenience, safety, and efficacy in severe infection. Teicoplanin appears to have lower toxicity and greater convenience; however, its widespread acceptance has been plagued by concerns over antimicrobial resistance, efficacy, and appropriate dosing. A review of available studies suggests that teicoplanin, when dosed at 6 mg/kg/day, is better tolerated than vancomycin 15 mg/kg/q12h; however, at these doses, it appears to be somewhat less effective than vancomycin in serious Staphylococcus aureus infection, such as endocarditis. Although higher doses of teicoplanin, 12 mg/kg/day to 30 mg/kg/day, have been associated with efficacy comparable to that of vancomycin in serious S. aureus infections, such doses may eliminate some of the safety advantages conferred by lower teicoplanin doses. Teicoplanin has been associated with resistance among coagulase-negative staphylococci and the selection of resistance in S. aureus. There is some evidence that widespread use of teicoplanin might accelerate the development of S. aureus resistance to both teicoplanin and vancomycin. The selection of an appropriate glycopeptide in an individual patient should be based not only on convenience, but also on a determination of optimal efficacy, safety at an efficacious dose, and the potential for resistance.

Systemic candidiasis in cardiac surgery patients

OBJECTIVE

To examine the frequency, predisposing factors and consequences of systemic candidiasis in cardiac surgery patients. We also examined fluconazole efficacy in the treatment of disseminated fungal disease.

METHODS

A total of 2615 adult patients of mean +/- S.D. age 60.8 +/- 8.7 years who underwent open heart surgery between July 1993 and April 1995, were enrolled in the initial protocol. Patients were divided in two groups according to length of stay in the intensive care unit (ICU). The cut-off was a length of stay of 9 days.

RESULTS

In the group of patients with prolonged stay (n = 54), 11 patients (20.3%) developed systemic candidiasis, usually after the twentieth postoperative day. Predisposing factors were patient age, history of diabetes mellitus, presence of central venous catheters, prolonged mechanical ventilatory support, prolonged ICU stay, and administration of antibiotics and of total parenteral nutrition for a prolonged period. The patients who developed systemic candidiasis had a median ICU and hospital stay of 58 and 60 days respectively. The mortality rate was 27.2%. Patients receiving fluconazole, improved and eventually negative cultures were obtained.

CONCLUSIONS

We concluded that a significant percentage of patients who remained in the cardiothoracic ICU for more than 9 days developed systemic candidiasis. Systemic candidiasis resulted in a significant prolongation of ICU and hospital length of stay, thus increasing extensively total hospitalization costs. Fluconazole seems to be an effective and well-tolerated agent in the treatment of severe life-threatening systemic candidiasis, and a very good alternative to amphotericin B, in cardiac surgery patients.

A modified PCR-based method for rapid non-radioactive detection of clinically important pathogens

We have devised a sensitive and rapid method for the detection of several bacterial pathogens in clinical specimens using PCR. This method has been named Direct Labeling and Detection Procedure (DLDP) and is based on the direct incorporation of a nonradioactive digoxigenin label (DIG-11-dUTP) into a microbial species-specific gene fragment during amplification. Following amplification, the resulting PCR products are cleansed of nonincorporated DIG-11-dUTP, spotted onto a nylon membrane, fixed by UV-crosslinking and the labeled DNA is visualized by digoxigenin detection reagents. Using cultivated reference bacteria (Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa) we were able to demonstrate a rapid and sensitive detection of < 20 CFU of bacteria in human secretions (sputum, urine, mucous). The present study suggests that DLDP can be used as a reliable method for indication of bacteria in clinical or environmental specimens with the proviso that the selected corresponding oligonucleotide primers provide amplification of strong species-specific genes.

The value of intracranial pressure monitoring in acute hemispheric stroke

BACKGROUND AND PURPOSE

Persistently elevated intracranial pressure (ICP) has been associated with poor clinical outcome after severe brain injury, such as neurotrauma, intracerebral hemorrhage, and subarachnoidal hemorrhage. Although ICP monitoring is increasingly being used in intensive care treatment of patients with ischemic stroke, its value has not been established.

PATIENTS AND METHODS

The clinical course of 48 patients with the clinical signs of increased ICP due to large hemispheric or middle cerebral artery territory infarction defined by CT and subjected to ICP monitoring was prospectively evaluated. Epidural ICP probes were inserted ipsilaterally to the site of primary brain injury in all and also contralaterally in seven patients. Initial clinical presentation was assessed by the Scandinavian Stroke Scale (SSS) and the Glasgow Coma Score (GCS). All patients were treated according to a standardized treatment protocol for elevated ICP. ICP values were correlated with the clinical presentation at the time point of deterioration, with outcome, and with CT findings. Different treatment strategies to lower ICP were analyzed as to their effectiveness.

RESULTS

Only nine of the 48 patients survived the infarct (19%). The cause of death was transtentorial herniation with subsequent brain death in all 39 patients. The patients' mean SSS on admission was 20.6 (survivors 21.5 +/- 5.6, nonsurvivors 19.8 +/- 6.5). In all patients clinical signs of herniation preceded the increase in ICP. Patients with ICP values > 35 mm Hg did not survive. CT changes did not always correspond with the measured ICP values. All medical strategies to lower ICP, including osmotherapy, hyperventilation, THAM-buffer, and barbiturates, were initially effective, but only in a minority of patients was ICP control sustained.

CONCLUSIONS

ICP monitoring of large hemispheric infarction can predict clinical outcome. Pharmacologic intervention had no sustained effect. ICP monitoring was not helpful in guiding long-term treatment of increased ICP. It remains doubtful that ICP monitoring in acute ischemic stroke has a positive influence on clinical outcome.