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Wound infection in cardiac surgery is a continuing problem despite improvements in surgical technique. The risk factors for, and appearance of, the infected wound differ from operations in other specialties. A robust definition is required for successful surveillance but many are open to different interpretations. At UCLH, comparison between UK and US definitions shows marked differences in patients defined as infected. Surveillance with feedback is effective if conducted over several years, but a high proportion of infected wounds are only identified during post-discharge follow-up. Deteriorating performance of an individual surgeon can be detected and interventions focused on improving faults identified during data collection. Often highlighting the problem is sufficient to reverse the trend, but the process of audit and control is becoming more important as accountability and performance is demanded by primary care providers and patients.

The paper presents some basic data on hospital infections and their influence in evaluation of hospital functioning. The most common infections, microorganism which are the cause of them, the role of patient immunological state, ways of spreading infections and ways of preventing them have been presented.

Objectives: To quantify the surgical infection rate and to identify risk factors associated with surgical site infection., Methods: We conducted a case-control study of all surgical patients between January 1, 1993, and June 30, 1994. The frequency of surgical site infection per 100 surgeries was calculated. The odds ratio (OR) was estimated by using logistic regression analysis., Setting: A 130-bed tertiary-care teaching hospital for adult patients with cancer., Results: The study followed 3372 surgeries. Three hundred thirteen patients had a surgical site infection (rate per 100 surgeries: 9. 30). The risk factors associated with surgical site infection were diabetes mellitus (OR = 2.5, 95% confidence interval [CI] = 1.27-4. 91), obesity (OR = 1.76, 95% CI = 1.14-2.7), presence of surgical drains for >5 and <16 days (OR = 1.84, 95% CI = 1.02-3.31), and presence of surgical drains for >/=16 days (OR = 2.14, 95% CI = 1. 0-4.6). The bacteria most frequently isolated were Escherichia coli 38 (21.8% of the total of microorganisms found), Pseudomonas sp 22 (12.6%), Staphylococcus aureus 16 (9.2%), and coagulase-negative Staphylococcus 25 (13.6%). The coexistence of other nosocomial infections was greater among the cases (OR = 1.8, 95% CI = 1.1-3.1) than in the control group., Conclusions: The surgical site infection rate in our hospital is slightly higher than the rates reported for general hospitals. The risk factors associated with surgical site infection are similar to those previously reported. Diabetes mellitus, obesity, and prolonged presence of a surgical drain increased the risk of infection.

The aerobic and anaerobic microbiology of surgical-site infections (SSI) following spinal fusion was retrospectively studied. This was done by reviewing the clinical and microbiological records at the Naval Hospital in Bethesda, Md., from 1980 to 1992. Aspirates of pus from 25 infection sites showed bacterial growth. Aerobic bacteria only were recovered from 9 (36%) specimens, anaerobic bacteria only were recovered from 4 (16%), and mixed aerobic and anaerobic bacteria were recovered from 12 (48%). Sixty isolates were recovered: 38 aerobes (1.5 isolates per specimen) and 22 anaerobes (0.9 isolate per specimen). The predominant aerobes were Escherichia coli (n = 8) and Proteus sp. (n = 7). The predominant anaerobes were Bacteroides fragilis group (n = 9) and Peptostreptococcus sp. (n = 6) isolates. An increase in recovery of E. coli and B. fragilis was noted in patients with bowel or bladder incontinence. This study highlights the polymicrobial nature of SSI and the importance of anaerobic bacteria in SSI following spinal fusion.

Patients and Methods: In a prospective protocol 25 consecutive patients with diffuse peritonitis were treated in the Surgical Clinic of the RWT-University in Aachen, Germany, from January to December 1995. According to the "Mannheim Peritonitis Score" three different stages were treated with different surgical procedures and a selective antibiotic regimen. Group-A patients with prognostically favorable peritonitis (MPS 0-20) were treated with the so-called standard procedure, group-B patients (MPS: 21-29) with closed postoperative lavage. The antibiotic regimen was cefotaxime (2 x 2 g) and metronidazole (2 x 500 mg) for both group-A and group-B patients. Severe group-C cases (MPS > 29) were treated with the so-called Etappenlavage (multiple reexplorations and intra-operative lavage) and received a combination of three antibiotics (2 x 2 g cefotaxime; 2 x 500 mg metronidazole and 2 x 200 mg ofloxacin)., Results: Eight patients belonged to group A, 10 to group B, and 7 to group C. The mortality was 0% (group A), 20% (group B), and 29% (group C), respectively. The actual overall mortality of the whole group was 16% (4/25). The statistically expected mortality was 36%, according to the APACHE-II-Score (P = 0.0982).

Infection is an important arbiter of success or failure of surgical practice and the incidence of infection is incorporated into all surgical audit systems. If audit is to be of value the outcome end points of clinical practice must be defined. We have attempted to derive clinical definitions suitable for bedside diagnosis of infection and believe that these should bs supported by, but not be dependent upon, the results of laboratory or imaging techniques. The proposed definitions are intended to form the basis for clinical audit and to allow meaningful comparisons to be made on clear clinical criteria.

A multicenter study was undertaken to analyze postoperative wound infections after posterior spinal instrumentation and fusion. The infection rate of these procedures has been documented in multiple reports. From these results, a classification scheme was developed that can guide therapy and determine the populations at risk. The patients were categorized according to two parameters, the first being the severity or type of infection, and the second being the host response or physiologic classification of the patient. This classification scheme is based on the clinical staging system for adult osteomyelitis developed by Cierny. The severity of infection is divided into three groups. Group 1 is a single-organism infection, either superficial or deep. Group 2 is a multiple-organism, deep infection. Group 3 is multiple organisms with myonecrosis. The host response, likewise, is divided into three classes. Class A is a host with normal systemic defenses, metabolic capabilities, and vascularity. Class B patients demonstrate local or multiple systemic diseases, including cigarette smoking. Class C requires an immunocompromised or severely malnourished host. Our data have demonstrated that single organisms, Group 1, generally can be dealt with by single irrigation and debridement, and closure over suction drainage tubes without the use of an inflow-irrigation system. The Group 2 patients, with multiple organisms and deep infection, required an average of three irrigation debridements. They have a higher percentage of successful closures with closed inflow-outflow suction irrigation systems when compared to simple suction drainage systems without constant inflow irrigation. Multiple-organism infections with myonecrosis, Group 3, are exceedingly difficult to manage, and portend a poor outcome. Patients without normal host defenses, Classes B and C, are at high risk for developing postoperative wound infection. Specifically, this study demonstrated that cigarette smoking may be a significant risk factor.

A prospective 2-year surveillance of 7129 wounds was conducted on all surgical services of the University Hospital in Seattle to determine the postoperative infection rates by surgical wound category. Rates on all services for clean (0.8%), clean-contaminated (3.4%), contaminated (3.6%), and dirty (9.9%) wounds were recorded and compared to rates reported in the surgical literature. The overall wound infection rate was 1.7%. When the incidence of infection for a specific service in a category was observed to be in excess of a previously reported upper rate, patient charts were critically reviewed to determine if host, pathogen, or technical factors could be implicated in the excessive infection rates. Extending postoperative wound surveillance to include critical chart analysis in these categories provides hospital staff members responsible for infection control the opportunity to organize corrective measures against excessive rates in a broader category of wounds.

Findings in seven patients with intraoperative bacterial invasions are reported. These invasions were classified in three stages of severity: (1) According to the literature it may be assumed that clinically undetectable invasion occurs in more than 10% of all operations. The bacteria detected in one case may have been a secondary finding in an electron-microscopic study. (2) A benign endophthalmitis caused by Staphylococcus epidermidis was found in three patients. The symptoms initially prompted the incorrect diagnosis "toxic lens syndrome". Cells resembling leukocytes were detected on the lenses by light microscopy. Following explantation of the lens and the posterior capsule, patients' vision slowly recovered to an average of 0.8. (3) Of three patients with fulminant panophthalmitis caused by Enterococci and/or Staphylococcus epidermidis, only one patient re-attained 0.5 vision, after two weeks; in the second case vision remained restricted to "hand movements", and in the third the eye had to be enucleated.