[Spectrum of pathogens in postoperative complications of visceral surgery : The problem of multidrug resistance]

In general surgery the etiology of surgical site infections has not significantly changed over the last 30 years. Gram-positive bacteria, e.g. coagulase negative staphylococci (CNS), Staphylococcus aureus and Enterococcus spp. as well as Gram-negative bacteria, e.g. Escherichia coli, Enterobacter spp., Klebsiella spp. and Pseudomonas aeruginosa, are the most common findings. Although in general surgery 10% of the S. aureus causing postoperative wound infections were methicillin resistant (MRSA), no cases of multidrug-resistant Gram-negative (MRGN) bacteria were reported. Yeasts (particularly Candida spp.) are rarely the pathogen causing surgical site infections (≤3%) and concomitant risk factors are typical (e.g. diabetes, chemotherapy, immunosuppression and malnutrition). Viruses are rarely the cause of surgical site infections. Transmission can occur by HBV, HCV or HIV positive surgical staff or in organ transplantations and postoperative reactivation of persistent infections is possible (especially for HBV, HCV, CMV, EBV and HIV). The principles for prevention of surgical site infections are dealt with as consequences of preoperative colonization by MRSA, methicillin-sensitive S. aureus (MSSA) and MRGN and reviewed with respect to screening, perioperative antibiotic prophylaxis and decolonization. In nosocomial peritonitis, the selection of antibiotics should consider previous antibiotic treatment. A single intra-abdominal detection of Candida spp. usually does not require antimycotic treatment in postoperatively stable and immunocompetent patients but is recommended in severe community-acquired or nosocomial peritonitis. Viral infections can be avoided by screening of organ donors and serological surveillance of surgery personnel.

The impact of systemic fungal infection in patients with perforated oesophagus

INTRODUCTION

Perforated oesophagus is a surgical emergency with significant morbidity and mortality. Systemic fungal infection represents a poor response to the magnitude of the insult, which adds significantly to the risk of morbidity and mortality in these patients. We reviewed our experience with this group of patients over a six-year period in a tertiary referral centre.

METHODS

A retrospective clinical review was conducted of patients who were admitted following a ruptured oesophagus over a period of six years (January 2002 - January 2008).

RESULTS

We had 27 admissions (18 men and 9 women) following an isolated perforated oesophagus to our unit. The median patient age was 65 years (range: 22-87 years). The majority (n=24, 89%) presented with spontaneous perforations (Boerhaave's syndrome) and three (11%) were iatrogenic. Fungal organisms, predominantly Candida albicans, were positively cultured in pleural or blood samples in 16 (59%) of the 27 patients. Fourteen patients grew yeasts within the first seven days while two showed a delayed growth after ten days. Overall mortality was 5 out of 27 patients (19%). There was no mortality among the group that did not grow yeasts in their blood/pleural fluid while mortality was 31% (5/16) in the group with systemic fungal infection (p<0.001). A positive fungal culture was also associated with increase ventilation time, intensive care unit stay and inpatient hospital stay but not an increased rate of complications.

CONCLUSIONS

Systemic fungal infection in patients with a ruptured oesophagus affects a significant proportion of these patients and carries a poor prognosis despite advanced critical care interventions. It may represent a general marker of poor host response to a major insult but can add to mortality and morbidity. It is worth considering adding antifungal therapy empirically at an early stage to antimicrobials in patients with an established diagnosis of a perforated oesophagus.

Hospital-acquired candidemia in HIV-infected patients. Incidence, risk factors and predictors of outcome

A retrospective case-control study was performed to analyze hospital-acquired candidemia in HIV-positive patients. To understand the impact of Highly Active Antiretroviral Therapy (HAART) on the incidence of nosocomial candidemia, two time periods were compared: A (1992-1996) and B (1997-2001). 32 out of 38 (84%) cases of candidemia were hospital-related. A significant reduction in the incidence of all cases of hospital-acquired candidemia has been observed in the post-HAART in respect to pre-HAART period (0.09 episodes vs. 1.1 per 100/py). Multivariate analysis showed that the presence of central venous catheter was the only variable independently associated with the development of nosocomial candidemia. The overall mortality rate was 59%. Univariate analysis indicated three prognostic indicators: presence of concomitant opportunistic infections, isolation of non-albicans Candida species; neutropenia. Multivariate analysis of prognostic indicators showed that isolation of non-albicans Candida species is the only independent variable. Despite the use of HAART, this disease still represents a severe complication of advanced stage of AIDS.

Sepsis in burned patients

A prospective study was conducted from June 2001 to May 2002 at the Burns Unit of Hospital Regional da Asa Norte, Brasília, Brazil. During the period of the study, 252 patients were treated at the Burns Unit, 49 (19.4%) developed clinically and microbiologically proven sepsis. Twenty-six (53.1%) were males and 23 (46.9%) females with a mean age of 22 years (range one to 89 years) and mean burned body surface area of 37.7 +/- 18.4% (range 7 to 84%). Forty-three patients had flame burns, five a scald and one an electric burn. These 49 patients had a total of 62 septic episodes. Forty (81.6%) patients had only one and nine (18.4%) had up to three episodes of sepsis. Thirty (61.2%) patients had their first septicemic episode either earlier or by one week postburn. Out of 62 septic episodes, 58 were due to bacteria and four due to Candida sp. The most common bacteria isolated from blood culture were Staphylococccus aureus, coagulase-negative Staphylococcus, Acinetobacter baumannii, Enterobacter cloacae and Klebsiella pneumoniae. Eleven (18.9%) episodes were due to oxacillin resistant Staphylococcus aureus. Acinetobacter baumannii was sensitive to ampicillin/sulbactam in 71.4% and to imipenem in 85.7% of the cases. The primary foci of sepsis were the burn wound in 15 (24.2%) episodes. The most common clinical findings of sepsis in these patients were fever, dyspnea, hypotension and oliguria. The most common laboratory findings of these patients were anemia, leukocytosis, hypoalbuminemia and thrombocytopenia. Twelve (24.5%) patients died. The appropriate knowledge of clinical, epidemiological, laboratorial and microbiological aspects of sepsis in burned patients permits an adequate diagnosis and treatment of this complication.

Determinants of Candidemia and Candidemia-Related Death in Cardiothoracic ICU Patients

STUDY OBJECTIVES

To develop and prospectively validate models of independent predictors of candidemia and candidemia-related death in cardiothoracic ICU (CICU) patients.

DESIGN

(1) An initial, prospective, one-center, case-control, independent predictor-model determining study; and (2) a prospective, two-center, model-validation study.

SETTING

The initial study was performed at the 14-bed CICU of the Onassis Cardiac Surgery Center, Athens, Greece; the model-validation study was performed at the Onassis Cardiac Surgery Center CICU and the 12-bed CICU of Henry Dunant General Hospital, Athens, Greece.

PATIENTS

In the initial study, 4,312 patients admitted to the Onassis Center CICU between March 1997 and October 1999 were considered for enrollment; 30 candidemic and 120 control patients (case/control ratio, 1/4) matched according to potential confounders were ultimately enrolled. In the model-validation study, 2,087 patients admitted to the Onassis and Henry Dunant CICUs between November 1999 and May 2002 were prospectively enrolled.

MEASUREMENTS AND RESULTS

Models of predictors of candidemia and associated death were constructed with stepwise logistic regression and subsequently validated. Independent candidemia predictors were ongoing invasive mechanical ventilation (IMV) > OR =10 days, hospital-acquired bacterial infection and/or bacteremia, cardiopulmonary bypass duration > 120 min, and diabetes mellitus. Model performance was as follows: sensitivity, 53.3%/57.9%; specificity, 100%/100%; positive predictive value (PPV), 100%/100%; negative predictive value (NPV), 88.9%/99.6%; and accuracy, 90.1%/99.6% (initial/model-validation study values, respectively). IMV > or =10 days and hospital-acquired bacterial infection/bacteremia were the two strongest candidemia predictors. APACHE (acute physiology and chronic health evaluation) II score > or =30 at candidemia onset independently predicted candidemia-related death with 80.0%/85.7% sensitivity, 80%/75% specificity, 66.7%/66.7% PPV, 88.9%/88.9% NPV, and 80.0%/78.9% accuracy (initial/model-validation study values, respectively).

CONCLUSIONS

We provided a set of easily determinable independent predictors of the occurrence of candidemia in CICU patients. Our results provide a rationale for implementing preventive measures in the form of independent predictor control, and initiating antifungal prophylaxis in high-risk CICU patients.

Risk factors in surgery

Improved surgical and anesthetic techniques and postoperative care have not significantly changed wound infection rates over the last 30 years. Many risk factors, related both to the host and to the surgical practice, have been identified in different studies. Control of nosocomial infections has become more challenging recently, due to a widespread bacterial resistance to antibiotics and to more frequent surgical indications in elderly patients at increased risk. A change in the microbiology of postoperative infections has also been noticed, characterized by a greater incidence of infections caused by methicillin-resistant Staphylococcus aureus, by polymicrobic flora and by fungi. This paper reviews the most important risk factors encountered in general surgery, that we observed during a 6-year prospective study of wound infection carried out in our Department of Surgery at the University of Insubria in Varese. Furthermore, the epidemiologic data on wound infections recorded in 4,002 patients undergoing general surgical procedures (mostly gastrointestinal operations), are presented and discussed.

Risk factors for candidal bloodstream infections in surgical intensive care unit patients: the NEMIS prospective multicenter study. The National Epidemiology of Mycosis Survey

To assess risk factors for development of candidal blood stream infections (CBSIs), a prospective cohort study was performed at 6 sites that involved all patients admitted to the surgical intensive care unit (SICU) for >48 h over a 2-year period. Among 4276 such patients, 42 CBSIs occurred (9.82 CBSIs per 1000 admissions). The overall incidence was 0.98 CBSIs per 1000 patient days and 1.42 per 1000 SICU days with a central venous catheter in place. In multivariate analysis, factors independently associated with increased risk of CBSI included prior surgery (relative risk [RR], 7.3), acute renal failure (RR, 4.2), receipt of parenteral nutrition (RR, 3.6), and, for patients who had undergone surgery, presence of a triple lumen catheter (RR, 5.4). Receipt of an antifungal agent was associated with decreased risk (RR, 0.3). Prospective clinical studies are needed to identify which antifungal agents are most protective and which high-risk patients will benefit from antifungal prophylaxis.

Fungemia in cancer patients undergoing chemotherapy versus surgery: risk factors, etiology and outcome

26 patients with fungemia and cancer treated with chemotherapy (group A) were compared to 25 patients with fungemia and cancer treated with surgery (group B), to assess differences in etiology, risk factors and outcome. Candida albicans was responsible for 42% of fungemias in group A, and for 92% of fungemias in group B (p < 0.005). Breakthrough fungemia occurring during antifungal prophylaxis appeared in 46.6% of group A vs 12% of group B (p < 0.02). There was significant difference in outcome between the groups: 20% of patients after surgery vs 7.7% of those after chemotherapy died from fungemia (p < 0.04). Most common risk factors recorded in both groups were catheter insertion and previous therapy with broad spectrum antibiotics.

Assessing risk factors for systemic fungal infections

The incidence of invasive fungal infection has increased in recent years. Most infections are caused by Candida albicans and Aspergillus spp. but the emergence of other fungal infections is changing the spectrum of disease. Immunosuppression and breakdown of anatomical barriers such as the skin are the major risk factors for fungal infections. Health care workers encounter at-risk patients in various settings, including AIDS clinics and intensive care, transplantation and oncology units. Patients with prolonged and deep neutropenia (haematological malignancy patients) are most at risk and are therefore most likely to receive prophylactic therapy. Practical measures can be taken to avoid exposing the patient to fungi (air filtration, regular hand washing, avoiding plants and flowers) and antifungal agents can be administered to prevent systemic fungal infection. Most fungal infections have non-specific symptoms; this makes recognition of the signs and symptoms of the disease important but also makes diagnosis difficult and empirical treatment necessary. Some antifungal agents have limitations but new formulations will improve therapy and play a key role in future antifungal strategies.

Candidemia in pediatric surgery patients

Candida spp. are the fourth leading cause of bloodstream infection. While the literature on neonatal candidemia is abundant, its prevalence in pediatric surgery cases is hardly mentioned. This study was carried out over a 5-year period to evaluate the prevalence of candidemia in pediatric surgery intensive care unit patients (ICU), and to examine both the neonatal and hospital risk factors for developing candidemia in comparison to control groups of patients with either no infection or with bacteremia, type and outcome of therapy. A total of 1,359 pediatric surgery patients admitted to the ICU and high dependency unit (HDU) were included in the study. Using relevant specimens from them, a microbiological survey was carried out on admission and weekly thereafter. Twenty-five patients developed candidemia during the study period. Twenty-one of them were admitted to ICU. Nine were low birth weight and immature neonates. All 25 patients had underlying disease, most involving the gastroentestinal tract and requiring surgical intervention. All patients had been given broad-spectrum beta-lactam antibiotics with or without aminoglycosides and an anti-anaerobic drug prior to candidemia. The data show that patients who were not infected had very few risk factors that could predispose to candidemia. The bacteremic group of patients had more risk factors: mainly ICU stay, prior antibiotic therapy or GI surgery. The candidemia patients outnumbered these two groups in both neonatal and hospital risk factors. Twenty-three candidemia patients had received amphotericin B and 2 had fluconazole. Seventeen of them improved and the rest expired during therapy. Fourteen of the Candida isolated were C. albicans while the rest belonged to other Candida spp. dominated by C. parapsilosis. In conclusion, candidemia was infrequent in pediatric surgery patients. ICU stay, GI surgery and prior broad-spectrum antibiotic therapy were important risk factors.

High level of recovery of fungi from water and dialysate in haemodialysis units

The counts of yeasts and filamentous fungi were investigated in the municipal water supplies of haemodialysis centres, in the treated water and the dialysate from all 85 haemodialysis units in Greece, in order to estimate their occurrence, their correlation with contamination indicator bacteria and other influencing factors. Filamentous fungi and yeasts were isolated from 69 (81.2%) and from three (3.5%) feed water samples, from 74 (87.1%) and seven (8.2%) treated water samples and from 66 (77.7%) and 11 (12.9%) dialysate samples respectively. Aspergillus spp and Penicillium spp were the most frequent moulds, while Candida spp were the prevailing yeasts. The occurrence of yeasts was significantly higher in dialysate than in tap water samples. Counts of filamentous fungi in all 255 samples were significantly correlated with the counts of total heterotrophic bacteria and enterococci, whereas the counts of yeasts were correlated with faecal coliforms, total heterotrophic bacteria, as well as enterococci, Pseudomonas spp and total coliforms, while no correlation was detected with the age of either haemodialysis units, the age of water treatment system, the number of artificial kidney machines or the components of the water purification system. High recovery of fungi from haemodialysis aqueous environments implies a potential risk for haemodialysis patients and indicates the need for continuous maintenance and monitoring.

Fungal empyema thoracis: an emerging clinical entity

STUDY OBJECTIVES

To analyze the clinical spectra, pathogenesis, treatment, outcome, and prognostic factors of fungal empyema thoracis.

DESIGN

The medical records of patients with positive fungal cultures from pleural effusions were retrospectively analyzed.

SETTING

A university-based tertiary care hospital in Taipei, Taiwan.

PATIENTS AND METHODS

From January 1990 through December 1997, patients diagnosed with fungal empyema were included in this study. The criteria for diagnosis of fungal empyema thoracis were as follows: (1) isolation of a fungal species from the pleural effusion; (2) significant signs of infection, such as fever (body temperature > 38.3 degrees C) and leukocytosis (white blood cell > 10,000/microL); and (3) isolation of the same mold species from pleural effusion on more than one occasion, or from pleural effusion and other specimens such as blood, sputum, or surgical wounds that showed evidence of tissue invasion.

RESULTS

Sixty-seven patients with fungal empyema thoracis were included. Their mean age was 54 years (range, 2 weeks to 93 years), and 64% (43 patients) were men. Fifty-seven patients (85%) had various underlying diseases, and 18 (27%) had more than one immunocompromising condition. A total of 73 fungal isolates were recovered from pleural effusion; the most commonly encountered were Candida species (47 isolates, 64%), Torulopsis glabrata (13 isolates, 18%), and Aspergillus species (9 isolates, 12%). Candida albicans (28 isolates) was the most common Candida species, followed by Candida tropicalis (13 isolates). Six patients (9%) had two fungal strains isolated, and 16 (24%) had concomitant bacterial empyema thoracis. Eighteen patients (27%) had concurrent fungemia. Most (56 patients, 84%) cases of fungal empyema thoracis were nosocomial, and many case (43 patients, 64%) were acquired in ICUs. Abdominal disease (20 patients, 30%), especially previous abdominal surgery and GI perforation (12% and 10%, respectively), was the most common cause of fungal empyema thoracis, followed by bronchopulmonary infection (15 patients, 22%) and chest surgery (12 patients, 18%). Forty-nine patients (73%) received systemic antifungal therapy, and 38 (57%) underwent closed drainage therapy. Eleven patients (16%) underwent pleural irrigation with normal saline solution, povidone-iodine solution, or antifungal agents. Six patients (9%) finally received decortication. All patients receiving surgery or pleural irrigation with antifungal agents survived. Despite the aforementioned management, the crude mortality was high (73%). Multivariate analysis showed a significantly increased risk of death in immunocompromised patients (relative risk, 1.58; p < 0.005) and those with respiratory failure (relative risk, 2.31; p < 0.001). Systemic antifungal therapy was associated with a significantly lower risk of death (relative risk, 0.69; p < 0.05).

CONCLUSION

These data imply an increasing incidence of fungal empyema thoracis in recent years and the necessity for aggressive treatment of patients with this disease.

Rare non-albicans Candida species detected in different clinical diagnoses

In working on the incidence of yeasts we excluded from the tested set C. albicans, C. krusei, C. parapsilosis and C. tropicalis on the basis of morphological and biochemical properties. We found 16 rare species of yeasts: C. claussenii (16), C. guilliermondii (10), C. robusta (9), C. pulcherrima (8), C. zeylanoides (4), C. glabrata (3), C. lusitaniae (3), C. catenulata (2), C. mesenterica (2), C. utilis (2), C. freyschussii, C. intermedia, C. kefyr, C. lipolytica, C. mogii, C. pseudotropicalis (1 for each). These yeasts were detected mainly in cases of premature babies (22) from the nasopharynx (13), from the rectum (4), from the skin (23), from wound drains and from blood (1 for each), with gynaecological diagnoses (15) and rarely other diagnoses, such as malignancy (5), hypertension and respiratory infections (4 for each), kidney transplantation (3), dialysis, haemolytic-uremic syndrome (2 for each), perforation of gastric ulcus, otitis, prostatitis, ulcus cruris, coma, spina bifida, peritonitis and hepatic failure from different clinical material.

Guideline for prevention of surgical site infection, 1999. Hospital Infection Control Practices Advisory Committee

The “Guideline for Prevention of Surgical Site Infection, 1999” presents the Centers for Disease Control and Prevention (CDC)'s recommendations for the prevention of surgical site infections (SSIs), formerly called surgical wound infections. This two-part guideline updates and replaces previous guidelines.

Part I, “Surgical Site Infection: An Overview,” describes the epidemiology, definitions, microbiology, pathogenesis, and surveillance of SSIs. Included is a detailed discussion of the pre-, intra-, and postoperative issues relevant to SSI genesis.

Low incidence of candidaemia among neutropenic patients treated for haematological diseases

Candida colonization and haematogenous infection were studied retrospectively in 277 patients with haematological diseases by reviewing the microbiological reports of fungal surveillance and blood cultures over a 4-year period. Most patients (83%) were colonized by Candida and in the majority (68%) the same Candida species was isolated from at least 2 body sites. However, candidaemia was diagnosed in only 3 patients. During the same period invasive aspergillosis was diagnosed in 7 patients. Possible causes for the low incidence of candidaemia were fluconazole prophylaxis, empirical amphotericin B and strict indication for antibacterial therapy.