The Role of Pulmonary Function Testing and Lung Imaging in the Long-Term Follow-Up of Patients with COVID-19 Pneumonia

BACKGROUND

Post-COVID-19 Interstitial Lung Disease (PC-ILD) is characterized by fibrotic-like signs at high-resolution computed tomography (HRCT) and pulmonary function tests (PFTs) abnormalities after SARS-CoV-2 infection. It is still not clear how frequent these tests should be performed to rule out long-term consequences of COVID-19 pneumonia.

OBJECTIVES

The aims of our study were to evaluate the incidence and risk factors of PC-ILD and possibly to propose a long-term follow-up program.

METHOD

One-hundred patients, hospitalized in our ward for moderate to critical COVID-19, underwent two follow-up visits at three and 15 months in which PFTs and HRCT were performed.

RESULTS

At the 15-month follow-up, 8% of patients showed residual radiological and functional signs consistent with PC-ILD. All but one of these patients had already demonstrated PFTs and HRCT alterations at first follow-up visit, and the last 1 patient showed worsening of lung function during follow-up. These findings highlight the negative predictive value of PFTs at 3-month follow-up for the development of PC-ILD. Aging, severity of COVID-19, and degree of pulmonary involvement during acute infection proved to be significant risk factors for developing PC-ILD.

CONCLUSIONS

Our study highlights the importance of PFTs in the long-term follow-up of patients affected by moderate to critical COVID-19 pneumonia. Further studies are needed to confirm our hypothesis that HRCT should be performed only in patients with PFTs abnormalities.

Conservative oxygen supplementation during Helmet CPAP therapy in patients with COVID-19 and respiratory failure: A pilot study

Background

Respiratory failure is a severe complication in COVID-19 pneumonia that, in addition to oxygen therapy, may require CPAP support. It has been postulated that COVID-19 lung injury may share some features with those observed in HALI. Thus, a correct target PaO2during oxygen supplementation may be crucial to protect the lung from further tissue damage. Aims of the study were: 1) to evaluate the effects of conservative oxygen supplementation during Helmet CPAP therapy on mortality and ICU admission in patients with COVID-19 and respiratory failure; 2) to evaluate the effect of conservative oxygen supplementation on new-onset organ failure and secondary pulmonary infections.

Methods

This was a single-center, historically controlled study of patients with severe respiratory failure due to COVID-19 pneumonia, receiving either conservative or non-conservative oxygen supplementation during Helmet CPAP. A cohort receiving conservative oxygen supplementation was studied prospectively in which oxygen supplementation was administered with a target PaO2<100 mmHg. Results of this cohort were compared with those of a cohort who had received liberal oxygen supplementation.

Results

Seventy-one patients were included in the conservative cohort and 75 in the non-conservative cohort. Mortality rate was lower in the conservative cohort (22.5%versus62.7%, p<0.001). Rates of ICU admission and new-onset rate organ failure were lower in conservative cohort (14.1%versus37.3%, p=0.001, and 9.9%versus45.3% p<0.001, respectively).

Conclusions

In patients with COVID-19 and severe respiratory failure, conservative oxygen supplementation during Helmet CPAP was associated to improved survival, lower ICU admission rate and less new-onset organ failure.

Elexacaftor-Tezacaftor-Ivacaftor corrects monocyte microbicidal deficiency in cystic fibrosis

Question

Cystic Fibrosis (CF), which is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), is characterized by chronic bacterial lung infection and inflammation. In CF, monocytes and monocyte-derived macrophages have been shown to display defective phagocytosis and antimicrobial activity against relevant lung pathogens, includingPseudomonas aeruginosa. Thus, we addressed the effect of the CFTR triple modulator therapy, Elexacaftor/Tezacaftor/Ivacaftor (ETI), on the activity of CF monocytes againstP. aeruginosa.

Materials/patients and Methods

Monocytes from people with CF (PWCF) before and after 1 and 6 months of ETI therapy were isolated from blood and infected withP. aeruginosato assess phagocytic activity and intracellular bacterial killing. The oxidative burst and IL-6 secretion were also determined. Monocytes from healthy controls were also included.

Results and answer to the question

Longitudinal analysis of the clinical parameters confirmed an improvement of lung function and lung microbiology by ETI. Both the phagocytic and microbicidal deficiencies of the CF monocytes also improved significantly, although not completely. Furthermore, we measured an exuberant oxidative burst in CF monocytes before therapy, which was reduced considerably by ETI. This led to an improvement of the ROS-dependent bactericidal activity. Inflammatory response to bacterial stimuli was also lowered compared to pre-therapy. PWCF on ETI therapy, in a real-life setting, in addition to clinical recovery, showed significant improvement in monocyte activity againstP. aeruginosa, which may have contributed to the overall effect of ETI on pulmonary disease. This also suggests that CF monocyte dysfunctions may be specifically targeted to ameliorate lung function in CF.

Early Markers of Cardiovascular Risk in Autosomal Dominant Polycystic Kidney Disease

BACKGROUND/AIMS

Cardiovascular disease is the most frequent cause of morbidity and mortality in autosomal dominant polycystic kidney disease (ADPKD) patients, often before the onset of renal failure, and the pathogenetic mechanism is not yet well elucidated. The aim of the study was to identify early and noninvasive markers of cardiovascular risk in young ADPKD patients, in the early stages of disease.

METHODS

A total of 26 patients with ADPKD and 24 control group, matched for age and sex, were enrolled, and we have assessed inflammatory indexes, mineral metabolism, metabolic state and markers of atherosclerosis and endothelial dysfunction (carotid intima media thickness (IMT), ankle brachial index (ABI), flow mediated dilation (FMD), renal resistive index (RRI), left ventricular mass index (LVMI)) and cardiopulmonary exercise testing (CPET), maximal O2 uptake (V'O2max), and O2 uptake at lactic acid threshold (V'O2@LT).

RESULTS

The ADPKD patients compared to control group, showed a significant higher mean value of LVMI, RRI, homocysteine (Hcy), Homeostasis Model Assessment-insulin resistance (HOMA-IR), serum uric acid (SUA), Cardiac-troponinT (cTnT) and intact parathyroid hormone (iPTH) (p<0.001, p<0.001, p<0.001, p<0.001, p<0.001, p=0.007, p=0.019; respectively), and a lower value of FMD and 25-hydroxyvitaminD (25-OH-VitD) (p<0.001, p<0.001) with reduced parameters of exercise tolerance, as V'O2max, V'O2max/Kg and V'O2max (% predicted) (p<0.001, p<0.001, p=0.018; respectively), and metabolic response indexes (V'O2@LT, V'O2 @LT%, V'O2@LT/Kg,) (p<0.001, p=0.14, p<0.001; respectively). Moreover, inflammatory indexes were significantly higher in ADPKD patients, and we found a positive correlation between HOMA-IR and C-reactive protein (CRP) (r=0.507, p=0.008), and a negative correlation between HOMA-IR and 25-OH-VitD (r=-0.585, p=0.002).

CONCLUSION

In our study, ADPKD patients, in the early stages of disease, showed a greater insulin resistance, endothelial dysfunction, inflammation and mineral metabolism disorders, respect to control group. Moreover, these patients presented reduced tolerance to stress, and decreased anaerobic threshold to CPET. Our results indicate a major and early cardiovascular risk in ADPKD patients. Therefore early and noninvasive markers of cardiovascular risk and CPET should be carried out, in ADPKD patients, in the early stages of disease, despite the cost implication.

Exercise tolerance in systemic sclerosis patients without pulmonary impairment: correlation with clinical variables

OBJECTIVES

In systemic sclerosis (SSc) patients pulmonary vasculopathy (PV) is present in the early stage of disease and impairs dilation of affected pulmonary blood vessels, impeding pulmonary blood flow during exercise. Abnormal gas exchange findings were early investigated by cardiopulmonary exercise test (CPET).

METHODS

A total of 34 female and 6 male [median age 49 (20-63) years] SSc patients with normal chest imaging and pulmonary function tests were enrolled. Twenty healthy controls age and sex matched [16 female and 4 male; median age 51 (35-73) years] were also recruited. All subjects underwent a full clinical examination, including a nailfold video capillaros copy (NVC). An incremental symptom-limited CPET was performed with estimation of minute ventilation (VE), workload (WR), peak oxygen uptake (pVO₂2), and ventilatory efficiency (VE/VCO2 slope).

RESULTS

A reduced exercise tolerance (pVO₂<80% of predicted) was documented in 18 out of 40 subjects (45%). Six out of 18 patients with a reduced exercise tolerance showed indirect signs of ventilation perfusion mismatch (VE/ VCO2 slope >34). Patients with digital ulcers (DUs) history showed VE/VCO₂slope values significantly higher [31.4 (18-39.6)] than in patients without DUs history [26.9 (22-29.4)] (p<0.0001). VE/VCO₂slope values also significantly differed between the three capillaroscopic groups: early [26.3 (18-29.4)], active [28 (26.8-39.6)], and late [32.9 (22.4-39)] (p<0.0001). A positive correlation was found between the VE/ VCO₂slope and both Disease Activity Index (p<0.0001, r=0.59) and Disease Severity Scale (p<0.0001, r=0.73).

CONCLUSIONS

In SSc patients without evidence of pulmonary and cardiac involvement, CPET might be useful in disclosing an early PV.

Methicillin-Resistant Staphylococcal Bacteremia in Patients with Hematologic Malignancies: Clinical and Microbiological Retrospective Comparative Analysis ofS. haemolyticus, S. epidermidisandS. aureus

Although Staphylococcus haemolyticus (SH) represents an emerging etiology of methicillin-resistant (MR) coagulase-negative staphylococcal nosocomial bacteremia, little is known of clinical significance of this infection. Thus, we performed case-control retrospective comparative analysis of MRSH bacteremias (MRSHB), methicillin-resistant S. epidermidis bacteremias (MRSEB), and methicillin-resistant S. aureus bacteremias (MRSAB) in patients with hematologic malignancies. Most patients in the three groups were neutropenic and had a central venous catheter (CVC) in place at the onset of bacteremia. However, MRSHB patients had a CVC in place prior to bacteremia for a time significantly more prolonged than MRSEB and MRSAB ones (p<0.05). Severe sepsis or septic shock were more common in patients with MRSAB as compared with MRSHB (p=0.02). Nosocomial attributable mortality rate was very low in the 3 study groups (0 to 5.4%) and only two patients developed metastatic infections. Overall, reduced susceptibility to teicoplanin was observed in 19 (47.5%) MRSH and in 4 (10%) MRSE isolates. Resistance to teicoplanin was observed in 6 isolates, all MRSH. Reduced susceptibility or resistance to vancomycin was observed in 2 isolates, both MRSH. All MRSA isolates were susceptible to the glycopeptides. Comparison between cases of bacteremia in patients with MRSH isolates with reduced susceptibility to teicoplanin and those with susceptible MRSH did not reveal significant differences in the clinical-microbiological response to teicoplanin therapy and outcome. Our results seem to suggest that MRSHB in hematologic patients is associated with low morbidity and mortality rates. MRSH frequently shows a reduced susceptibility to teicoplanin; however these in vitro data do not seem associated with an unfavorable clinical response to teicoplanin therapy for MRSHB in patients with hematologic malignancies.

Reliability of white blood cell scan in the follow-up of osteomyelitis

INTRODUCTION

The question of whether antibiotic treatment does or does not affect reliability of white blood cell scan (WBCS) to detect disease activity in clinical practice is still unanswered. Our aim was to study the relationship between scintigraphic findings of WBCS and antibiotic therapy in a group of patients affected with osteomyelitis (OM).

METHODS

We retrospectively reviewed 57 scans, performed in 18 patients affected by OM and who were on antibiotic treatment. The number of therapy weeks was calculated for each antibiotic. A comparison of results obtained during and after discontinuation of the antibiotic treatment was made. Overall sensitivity, specificity and accuracy of WBCS were calculated and compared with those obtained in patients undergoing therapy.

RESULTS

Forty-seven scans were performed during treatment and 10 scans after discontinuation of treatment. The scintigraphic results obtained during and after discontinuation of treatment were as follows: TN 14 and 8, TP 31 and 2, FN 2 and 0, FP 0 and 0, respectively. Sensitivity, specificity and accuracy of WBCS, calculated in all patients, were 94.3%, 100% and 96.5% respectively. In patients receiving antibiotic therapy, the same parameters were 93.9%, 100% and 95.7% respectively. In patients treated with antibiotics that can decrease leukocyte function, there were 10 TN, 14 TP, 2 FN and 0 FP, while in patients treated with antibiotics that have not effect on leukocyte function there were 4 TN, 17 TP, 0 FN and 0 FP.

CONCLUSION

The reliability of WBCS in the detection of disease activity during antibiotic treatment does not change significantly. It can be assumed that the influence of antibiotic therapy on labelled leukocyte behaviour is negligible.

In vitro activity of fosfomycin in combination with vancomycin or teicoplanin against Staphylococcus aureus isolated from device-associated infections unresponsive to glycopeptide therapy

Fosfomycin is a molecule that inhibits the early stage of peptidoglycan synthesis and shows a broad-spectrum bactericidal activity against Gram-positive and Gram-negative bacteria. Using the Killing-curve method, we tested the in vitro bactericidal activity of fosfomycin alone or in combination with vancomycin or teicoplanin at a concentration of 8 microg/mL, that is easily achievable in serum at standard dosing regimens, against seven methicillin-resistant Staphylococcus aureus strains, isolated from patients with well documented device-associated infections unresponsive to or relapsing after glycopeptide therapy. MICs of vancomycin ranged from 1 to 4 microg/mL, MICs of teicoplanin from 2 to 8 microg/mL; MICs of fosfomycin were 8 microg/mL for two strains and >128 microg/mL for the remaining strains. The seven strains proved tolerant when tested for vancomycin and teicoplanin used alone at 2x MIC concentration. Fosfomycin was bactericidal (reduction of 2 log of the inoculum) only against the two susceptible strains. In all cases both vancomycin and teicoplanin in combination with fosfomycin developed bactericidal synergism already at a concentration of 1x MIC. If these results are confirmed by in vivo experiments, the combination of fosfomycin with glycopeptides might be useful for treating device-associated infections, and in preventing the phenomenon of increasing MICs for glycopeptides.

Ethylene oxide sterilization of autologous bone flaps following decompressive craniectomy

INTRODUCTION

In patients undergoing decompressive craniectomy, the bone flap is temporarily preserved either in the subcutaneous tissue of the patient or frozen. However, there are some drawbacks related to these methods.

MATERIAL AND METHODS

In 16 patients in whom the bone flap was removed for decompressive craniectomy, the bone was firstly washed in hydrogen peroxide and then placed in hermetically-sealed bags and sterilized using ethylene oxide. The bone was repositioned after an average period of 4.3 months.

RESULTS

One patient sustained an infection of the surgical wound which required permanent exclusion of the bone flap. In all the others, esthetic and functional results were good after an average follow-up of 20 months. Control CT-scan of the bone flap demonstrated preservation of its structural features with fusion of the bone margins and revitalization of the flap. On MRI a subdural space was again visible.

CONCLUSIONS

Sterilization of the bone flap with ethylene oxide in patients undergoing decompressive craniectomy avoids some of the drawbacks related to the techniques currently used. The easiness, low cost, good aesthetic and functional results of this procedure make it a valid alternative to other techniques for preservation of autologous bone in decompressive craniectomies.

Conservative medical therapy of infections following osteosynthesis: a retrospective analysis of a six-year experience

The conventional therapeutic approach to bone infection associated with osteosynthesis is based on the idea that microbial eradication is most readily achieved by removal of the foreign material together with adequate antimicrobial therapy. This strategy usually requires implantation of external fixation devices with additional discomfort to the patient. We report our experience with conservative medical and antimicrobial therapy without removal of the osteosynthesis until adequate bone callus deposition is documented by bone radiography scan. Twenty patients with infections associated with intramedullary nailing (9 patients), screws and plate (9 patients) or screws (2 patients) were treated between 1995 to 2000. Osteosynthesis implantation sites were tibia (7 patients), femur (6 patients), femur and tibia (1 patient), humerus (1 patient), others (5 patients). Diagnosis of infection was based on clinical-microbiological evidence and confirmed by 99Tc-labeled leukocyte scan studies. Offending pathogens were Staphylococcus aureus 17 cases, Staphylococcus aureus + Escherichia coli, Staphylococcus epidermidis, unknown, 1 case each. Most infections were initially treated with intravenous or intramuscular teicoplanin +/- ciprofloxacin or rifampin followed by oral antimicrobial therapy usually with ciprofloxacin or minocycline plus rifampin. Mean duration of antimicrobial therapy was 27.7 weeks (range 12-64 weeks). All patients (100%) were cured, and none complained of side-effects requiring antibiotic therapy discontinuation. We conclude that conservative medical therapy is feasible for osteosynthesis-associated bone infection.

The role of preoperative Tc-99m HMPAO-labeled leukocyte total-body scans in aortic prosthetic reconstruction

PURPOSE

This study was performed to evaluate the utility of Tc-99m HMPAO-labeled leukocyte total-body scans (TBLS) for detecting remote septic foci before operation in patients undergoing aortofemoral vascular surgery.

MATERIALS AND METHODS

Fifty-eight patients were screened before operation for inflammatory or infective disease, and a clinical score was assigned to each patient. Each patient had TBLSs. The relation between the clinical score and the TBLS result was determined. Patients with positive results of the TBLSs were examined, and the causes of these findings were treated before surgery.

RESULTS

Ten of the 58 (17%) patients had a positive result of TBLSs. Of 31 patients with a clinical score of zero, 3 had positive findings of TBLS. No TBLS was positive in the 13 patients with a clinical score of 1. TBLS findings were positive in 7 of 14 of the combined patients with clinical scores of 2, 3, or 4. None of the patients showed signs of prosthetic vascular graft infection during the postoperative follow-up period.

CONCLUSIONS

In conclusion, TBLSs can be used before aortofemoral vascular surgery, but only in patients with high clinical scores for inflammatory or infective disease to identify relevant infective foci that could cause vascular graft infection.

Sternal wound infection revisited

Sternal wound infections (SWIs) can be subdivided into two types, superficial or deep, that require different treatments. The clinical diagnosis of superficial SWI is normally easy to perform, whereas the involvement of deep tissues is frequently difficult to detect. Therefore, there is a need for an imaging study that permits the assessment of SWIs and is able to distinguish between superficial and deep SWI. The present work was a prospective study aiming to evaluate the role of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leucocyte scan in SWI management. Twenty-eight patients with suspected SWIs were included in the study. On the basis of clinical examination they were subdivided into three groups: patients with signs of superficial SWI (group 1), patients with signs of superficial SWI and suspected deep infection (group 2) and patients with suspected deep SWI without superficial involvement (group 3). Ten patients previously submitted to median sternotomy, but without suspected SWI, were also included in the study as a control group (group 4). All patients with suspected SWI had bacteriological examinations of wound secretion, if present. In addition 99mTc-HMPAO labelled leucocyte scan was performed in all patients. The patients of groups 1, 2 and 3 were treated on the basis of the clinical signs and microbiological findings, independently of the scintigraphic results. The patients of group 4 did not receive treatment. The final assessment of infection was based on histological and microbiological findings or on long-term clinical follow-up. Sensitivity, specificity, accuracy and positive and negative predictive values for scintigraphic and non-scintigraphic results were calculated. In the diagnosis of superficial and deep SWI, clinical and microbiological examination (combined) yielded, respectively, a sensitivity of 68.7% and 100%, a specificity of 77.3% and 80.8%, an accuracy of 73.7% and 86.8%, a positive predictive value of 68.7% and 70.6% and a negative predictive value of 77.3% and 100%. The scintigraphic results obtained in superficial SWI yielded a sensitivity of 56.2%, a specificity of 90.9%, an accuracy of 76.3%, a positive predictive value of 81.8% and a negative predictive value of 74.1%, while, by contrast, in deep SWI all of these values were 100%. Therefore, one can conclude that 99mTc-HMPAO labelled leucocyte scan permits accurate diagnosis of deep SWI, solving the main clinical problem in this field. In the present study the categorisation of patients without taking into account 99mTc-HMPAO labelled leucocyte planar scan findings caused a non-negligible number of cases of superficial SWI to be treated as though they were deep SWI. This "overestimation" led to unnecessary surgery, increased and prolonged use of antibiotics with more (higher) toxicity and additional expense.

Clinical usefulness of technetium-99m-HMPAO-labeled leukocyte scan in prosthetic vascular graft infection

The infection of a prosthetic vascular graft (PVGI), although rare, is the most severe complication in reconstructive vascular surgery. The early diagnosis of this complication reduces the death rate from surgery. Aortofemoral graft infections differ clinically from peripheral graft infections in significant ways. The aim of this article is to evaluate separately the reliability of the 99mTc-HMPAO-labeled leukocyte scan or white blood cell count (WBC) in the early detection of both aortofemoral and peripheral graft infections.

METHODS

One hundred sixty-two WBCs were performed on 129 consecutive patients with suspected aortofemoral (122 scans) and peripheral (40 scans) graft infection and in a 12-patient control group. Patients with suspected PVGI were categorized into three groups on the basis of their signs and symptoms on readmission: (a) patients with specific signs of graft infection (Group A); (b) patients with nonspecific signs of graft infection (Group B); and (c) patients with anastomotic aneurysms (Group C). Gram's stains of the perigraft exudate and graft cultures were performed and used as the gold standard in patients who underwent surgery. An 18-mo clinical follow-up was done to assess the presence or absence of graft infection in patients who did not have surgery.

RESULTS

In patients with suspected aortofemoral graft infections, the overall sensitivity, specificity and accuracy of WBCs (Groups A, B, C) were 100%, 92.5% and 97.5%, respectively, whereas sensitivity, specificity and accuracy calculated in the patients with nonspecific signs of graft infection (Groups B, C) were 100%, 92.3% and 96.9%, respectively. In patients with suspected peripheral graft infections, sensitivity, specificity and accuracy were 100%.

CONCLUSION

The white blood cell scan seems a reliable diagnostic method for early diagnosis of PVGI, and it is more useful in aortofemoral graft infections.

In vitro susceptibility of Staphylococcus aureus isolated from blood to currently used antistaphylococcal drugs

Changes in antibiotic susceptibility was evaluated in 77 consecutive nosocomial clinical isolates of Staphylococcus aureus collected from 1986 to 1994 at the Umberto I Polyclinic of the University of Rome (63 isolates) and from 7 other Roman hospitals (14 isolates). Oxacillin resistance in these isolates increased from 39% during the 1980s to 69% during the 1990s. Significant increases in resistance to ciprofloxacin, clindamycin and rifampicin were observed among oxacillin-resistant strains. No resistance to glycopeptides was observed although both teicoplanin and vancomycin had slightly reduced antistaphylococcal activity.

Infections by ampicillin-resistant enterococci: a case-control study

We identified 17 (20%) of 83 consecutive enterococcal isolates from hospitalized patients with documented infection as high-level ampicillin-resistant enterococci (ARE). Of these, 16 isolates were identified as Enterococcus faecium and 1 isolate as Enterococcus raffinosus. A case-control study found no significant differences with respect to underlying diseases, central venous catheterization, nosocomial acquisition of the infection and sites of infection. Patients with ARE infection were older and had a higher inhospital fatality rate than those with ampicillin-susceptible Enterococcus (ASE) infection. Hospitalization in a surgery service (usually for an abdominal procedure), prolonged hospital stay, prior treatment with antibiotics (in particular imipenem and metronidazole), were also more frequent among patients with ARE infection. ARE isolates were more frequently resistant to imipenem, ciprofloxacin and streptomycin than ASE isolates.

High rate of oxacillin-resistant Staphylococcus aureus isolates in an Italian University Hospital

We reviewed our routine clinical laboratory records from January 1990 to March 1993 to evaluate the rate of oxacillin-resistance among nosocomial isolates of Staphylococcus aureus. Of 265 clinically significant isolates, 174 (65%) were oxacillin-resistant S. aureus (ORSA). Most of these strains were obtained from surgery patients and/or were isolated from surgical wounds. The isolations of S. aureus increased during the study period: 45 in 1990, 50 in 1991, 130 in 1992 and 40 in the first trimester of 1993. The annual rates of ORSA among S. aureus isolated varied from 62 to 68% through these years. Most ORSA isolates proved resistant to ciprofloxacin, gentamicin and rifampicin, and susceptible to vancomycin, netilmicin and cotrimoxazole. Based on these results, the need for a stringent application of infection control measures is outlined.

Aorto-femoral graft infections: a clinical and microbiological analysis

A 5-year experience of 19 aortic graft infections is reviewed. Of these, 13 (68%) had a late onset (more than 4 months after graft implantation) and usually presented with anastomotic pseudo-aneurysm or thrombosis. The remaining six infections (32%) had an early onset and presented more often with surgical wound infection. Aorto-enteric fistulae and inguinal sinus tracts were observed in both early and late onset infections. Coagulase-negative staphylococci (all slime negative, oxacillin susceptible strains) were the prevalent pathogens in both groups of infections and were isolated in six (32%) patients. Next most commonly seen were Pseudomonas aeruginosa in four (21%) patients, Enterococcus spp. in three (16%) patients, Staphylococcus aureus in three (16%) patients, other bacteria in six (32%) patients. No organisms were isolated in three (16%) patients. Mortality and major amputation rates were 47.3% and 31.6%, respectively. The therapeutic procedures included total graft removal (15 patients), partial graft excision (two patients), partial graft excision followed by total graft removal (one patient) and local treatment without graft removal (one patient). Six patients recovered, including two who underwent total graft removal associated with a non-conventional 'in situ' graft replacement and one patient treated conservatively with local treatment and antibiotics. The three patients undergoing partial graft excision showed signs of active infection of the residual graft.

Detection of aortic graft infection with leukocytes labeled with technetium 99m-hexametazime

PURPOSE

To reduce the rates of morbidity and mortality in aortic graft infection, a new diagnostic approach is needed to help identify low-grade stages, specifically when there are minimal or no clinical signs of overt infection. The aim of this study was to evaluate the role of technetium 99m--hexametazime white blood cell scanning (99mTc scanning) in detecting aortic graft infection, particularly in the low-grade stages.

METHODS AND RESULTS

Thirty-seven patients with suspected aortic graft infection were categorized into three groups according to their signs and symptoms on readmission. Ten patients (group A) had advanced graft infections that were correctly diagnosed by use of computed tomography (CT) scanning and 99mTc scanning and confirmed by intraoperative findings and culture results. Eighteen patients (group B) had nonspecific signs and symptoms of graft infection. Patients only underwent CT and 99mTc scanning for graft infection after standard clinical work-ups failed to reveal disease processes that accounted for the clinical symptoms. In this group of patients 99mTc scanning identified four cases of low-grade graft infection, which was confirmed by intraoperative findings and graft cultures. None of these four cases was confirmed by results of CT scanning. On an average 18-month follow-up in patients who did not undergo surgery graft infections developed. Nine patients (group C) had anastomotic aneurysms; CT scanning and 99mTc scanning correctly diagnosed five patients as being infected. The result of 99mTc scanning was false-positive in one patient.

CONCLUSIONS

The diagnostic accuracy of 99mTc scanning in patients who did not have specific signs of graft infection (groups B and C) was 100% for sensitivity, 94.4% for specificity, 90% for the positive predictive value, and 100% for the negative predictive value. 99mTc scanning seems to be a useful diagnostic technique for detecting aortic graft infection, particularly in low-grade stages.

Intravenous ciprofloxacin for the treatment of severe infections

Intravenous ciprofloxacin at a daily dosage of 400 mg divided in two doses was administered to 19 patients with severe infections caused by ciprofloxacin-susceptible bacteria. These infections included: 11 surgical would infections, 5 soft tissue infections, 2 respiratory tract infections, 1 urinary tract infection. The offending pathogens were: 8 coagulase-negative staphylococci, 3 Staphylococcus aureus, 3 Pseudomonas aeruginosa, 2 Proteus spp., 1 Escherichia coli, 1 Branhamella catarrhalis, 1 Klebsiella ozenae and 1 Serratia liquefaciens. Overall, 17 of 19 infections (89%) showed a satisfactory clinical response to trial therapy (15 cures and 2 improvements). Microbiological eradication was observed in 17 out of 20 isolated pathogens. Emergence of resistance to ciprofloxacin occurred in 1 coagulase-negative Staphylococcus and was associated with clinical failure. No side effects were observed. We conclude that intravenous ciprofloxacin may represent efficacious and safe therapy of severe infections; however close microbiological monitoring seems to be necessary to evaluate the emergence of resistance during quinolone therapy.

Clinical significance of intraoperative cultures of aneurysm walls and contents in elective abdominal aortic aneurysmectomy

To investigate the clinical significance of intraoperative cultures in elective abdominal aortic aneurysmectomy, we cultured the aneurysmal wall and contents in 90 patients undergoing vascular graft surgery. Prosthetic graft infection was documented in 1 out of 62 patients with negative cultures and in none of 28 patients with positive cultures (chi 2 = 0.4, p greater than 0.1). Bacterial growth was seen in neither of 2 inflammatory aneurysms, 3 of 14 atherosclerotic aneurysms and 2 of 5 aneurysms without specific features. A retrospective analysis of patients' charts aimed at finding possible risk factors failed to identify any correlation between results of cultures and length of hospitalization before surgery, time interval between angiography and surgery, route of angiography procedure or minutes of surgery before sample collection. We conclude that positive cultures may not imply clinical infection at the time of surgery and that prolonged post-operative organism-specific antibiotic therapy does not appear necessary to prevent graft contamination in patients undergoing elective abdominal aortic aneurysmectomy.

Alterations of coagulase-negative staphylococcal flora in cardiac surgery patients: comparative study between cefamandole and pefloxacin perioperative prophylaxis

The changes in coagulase-negative staphylococcal flora induced by cefamandole prophylaxis were compared with those induced by pefloxacin prophylaxis among patients undergoing heart valve surgery. Twenty-five patients (15 receiving cefamandole prophylaxis and 10 receiving pefloxacin prophylaxis) were included in the study. In the pefloxacin group, colonization rates in anterior nares and in chest skin or wound that were 60% and 50% respectively before surgery, became 50% and 20% respectively after surgery. In the cefamandole group, colonization rates in anterior nares and chest skin or wound were 53.3% and 60% respectively before surgery and became 53.3% and 40% respectively after surgery. Cefamandole did not appear to induce the emergence of oxacillin or pefloxacin resistant coagulase-negative staphylococcal colonization in any cultured site. On the other hand pefloxacin appeared somewhat more efficacious than cefamandole in eradicating staphylococcal flora of anterior nares and chest skin or wound. Pefloxacin and oxacillin resistant strains were found in the perianal area in 0% of patients before pefloxacin prophylaxis and in 70% of patients after pefloxacin prophylaxis. However, further studies are necessary to confirm the emergence of antibiotic resistant coagulase-negative staphylococci in the intestinal microflora after quinolone administration. The clinical implications of such apparently disturbing phenomenon remain to be evaluated.

Antimicrobial susceptibilities of Streptococcus species that cause septicemia in neutropenic patients

Sixty-three consecutive streptococcal blood isolates from neutropenic patients, represented mainly by viridans group streptococci, were evaluated in vitro for antibiotic susceptibility. Of these isolates, 79.3% were highly susceptible to penicillin (MIC, less than or equal to 0.12 microgram/ml). Overall, imipenem was the most active agent, followed by teicoplanin and vancomycin. All other agents showed decreased activity against streptococcal isolates that were not highly susceptible to penicillin.