Evaluation of Genetic Diversity of Candida spp. and Klebsiella spp. Isolated from the Denture Plaque of COPD Patients.

Yeast-like fungi and gram-negative bacilli are the most frequent potential pathogens of the respiratory tract isolated from the denture plaque of patients with chronic obstructive pulmonary disease (COPD). Dominant species among yeast-like fungi are Candida albicans and Candida tropicalis. Significant frequency is also exhibited by Klebsiella pneumoniae and Klebsiella oxytoca. The purpose of this study was to analyze genetic diversity of the strains of C. albicans, C. tropicalis, and Klebsiella spp. present in patients in stable phases of COPD. The analysis was conducted by the random amplified polymorphic DNA (RAPD) method on clinical strains isolated from patients with COPD and control patients in overall good health. Forty one strains of Candida albicans, 12 of Candida tropicalis, as well as 9 strains of K. pneumoniae and 7 of K. oxytoca were scrutinized. The dominant species in clinical material from COPD patients was Candida albicans with a substantial degree of variations of genetic profiles. On the basis of affinity analysis, 19 genetic types were identified within this strain. An analysis of the banding patterns among C. tropicalis strains indicated the existence of 6 genetic types. A considerable diversity of genetic profiles among Klebsiella spp. also was established. The genotype diversity of Klebsiella spp. strains may indicate the endogenic character of the majority of infections, regardless of the therapy applied for the underlying condition.

Diagnosis of Invasive Pulmonary Aspergillosis.

Culturing strains from clinical samples is the main method to diagnose invasive pulmonary aspergillosis. Detecting the galactomannan antigen in serum samples is an auxiliary examination. The goal of this study was to determine the frequency with which Aspergillus fumigatus was cultured in clinical samples taken from patients hospitalized in the the Infant Jesus Teaching Hospital in Warsaw, Poland, in the period of 2013-2014. Specimens from the respiratory tract and blood were cultured for mycological and serological assessments. Strain isolation was performed in chloramphenicol Sabouraud agar. Species identification was based on morphological traits in macro-cultures and on microscopic examination. The galactomannan antigen was detected by ELISA method. Out of 2000 clinical samples with positive mycological results, 200 were obtained from the respiratory tract. A. fumigatus was cultured in 13 cases from the respiratory group. Ten cases were cultured out of tracheal aspirates and three from bronchoalveolar lavage fluid. The galactomannan antigen was detected in a serum sample from only one out of the 13 patients with cultures positive for A. fumigatus. It also was detected in serum samples of three other patients in whom A. fumigatus culture yielded a negative result. We conclude that culture-confirmed invasive pulmonary aspergillosis represents a scarce finding. A. fumigatus cultured from clinical samples may not always be confirmed by ELISA assay and vice versa a positive ELISA result does not attest the successful culture.

The Prevalence of Oral Inflammation Among Denture Wearing Patients with Chronic Obstructive Pulmonary Disease.

Oral inflammation is an important contributor to the etiology of chronic obstructive pulmonary disease, which can impact patient's health status. Previous studies indicate that people with poor oral health are at higher risk for nosocomial pneumonia. Denture wearing is one promoting factor in the development of mucosal infections. Colonization of the denture plaque by Gram-negative bacteria, Candida spp., or other respiratory pathogens, occurring locally, may be aspirated to the lungs. The studies showed that chronic obstructive pulmonary disease (COPD) patients treated with combinations of medicines with corticosteroids more frequently suffer from Candida-associated denture stomatitis. Treatment of oral candidiasis in patients with COPD constitutes a therapeutic problem. Therefore, it is essential to pay attention to the condition of oral mucosal membrane and denture hygiene habits. The guidelines for care and maintenance of dentures for COPD patients are presented in this paper. The majority of patients required improvement of their prosthetic and oral hygiene. Standard oral hygiene procedures in relation to dentures, conducted for prophylaxis of stomatitis complicated by mucosal infection among immunocompromised patients, are essential to maintain healthy oral tissues. The elimination of traumatic denture action in dental office, compliance with oral and denture hygiene, proper use and storage of prosthetic appliances in a dry environment outside the oral cavity can reduce susceptibility to infection. Proper attention to hygiene, including brushing and rinsing the mouth, may also help prevent denture stomatitis in these patients.

Evaluation of blood culture media for the detection of fungi.

The aim of this study was to compare the utility of BACTEC™ Mycosis-IC/F (Mycosis), BACTEC™ Plus Aerobic/F (Aerobic), and BACTEC™ Plus Anaerobic/F (Anaerobic) media in the detection of fungi from simulated (obtained by the inoculation of tested media first with sterile sheep's blood and subsequently with one of 60 clinical yeast isolates) and clinical blood samples, taken during routine diagnostic examination in two hospitals. All tested strains grew on Mycosis as well as Aerobic bottles, and the time to detection obtained for Mycosis was significantly shorter (p < 0.05). The largest differences in the time to positivity was found for Candida glabrata and Cryptococcus neoformans, when Mycosis preceded Aerobic in 20-48 h (mean 35.5 h) and 0.7-64 h (mean 24 h), respectively. On the contrary, C. krusei were detected earlier in Aerobic media. In clinical samples, the detection of C. glabrata was also significantly faster in Mycosis than in Aerobic (29.22 ± 11.48 h compared to 86 ± 40 h). The media complement each other and, in 45% of clinical examination sets, a single positive medium was noted (25% in Mycosis and 19% in Aerobic). The study proved that both Aerobic and Mycosis media serve as the correct condition for the culture of fungi and that they varied significantly in the detection time of clinically important species. This result could suggest that the simultaneous use of Aerobic as well as Mycosis media may improve the time of diagnosis in many patients, especially those infected with C. glabrata or C. neoformans.

Influence of denture plaque biofilm on oral mucosal membrane in patients with chronic obstructive pulmonary disease.

Patients with chronic obstructive pulmonary disease (COPD) have the lower airways colonized with pathogenic bacteria in a stable period of the disease and during exacerbations. The etiology of bacterial exacerbations of COPD depends on the underlying disease, the frequency of exacerbations and antibiotic therapy. Microorganisms can be aspirated off the denture plaque biofilm into the lower respiratory tract and could reduce the patient's immunity and cause pneumonia. COPD patients, who are using acrylic dentures in oral cavity, are exposed to denture stomatitis and oral candidiasis. The aim of this study was to establish the composition of denture plaque biofilm and its impact on the oral mucosa in COPD patients. The study included patients in a stable phase of COPD using removable denture and the control group included healthy wearer's appliances. Examinations concerned the oral mucosal membrane and the hygienic condition of prosthetic restorations. Microbiological examinations were performed by taking a direct swab from the surface of acrylic dentures. Seventeen bacterial and fungal strains were isolated from denture plaque of COPD patients, which could be a reservoir of pathogens in the upper and lower airways. The results showed a greater frequency of prosthetic stomatitis complicated by mucosal infections among COPD patients compared to healthy subjects.

Molecular and phenotypic characteristics of methicillin-resistant Staphylococcus aureus strains isolated from hospitalized patients in transplantation wards.

OBJECTIVES: Hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) frequently causes therapeutic problems and provides information about the epidemiological condition of the ward. MATERIALS AND METHODS: HA-MRSA isolated from patients on transplantation wards in 1991, 1994, 1996, and from 2005 to 2007 were compared using molecular methods such as restriction fragment length polymorphism-pulse field gel electrophoresis, multilocus sequence typing (MLST), multiplex polymerase chain reaction (PCR) for detection type of staphylococcal chromosomal cassette mec, and PCR for detection. RESULTS: The analysis covered HA-MRSA strains, each from a different patient. All organisms were typed using molecular methods. MLST results were compared with an international base. The examined strains belonged to five different worldwide known clonal complexes: CC8 (78%), CC5 (12%), CC1 (4%), CC30 (2%), and CC51 (4%). All could be recognized as representatives of a clonal complex CC8 clones: ST239-III (sequence type 239 and SCCmec type III named EMRSA-1, -4, -11, Brasilian, Hungarian) occurred with a frequency of 35.9%, ST254-IV (EMRSA-10, Hannover) occurred in 33.3%, ST247-I (EMRSA-5,-7, Iberian) occurred in 20.5%, ST241-III (Finland-UK) occurred in 5.15%, and ST8-IV (EMRSA-2,-6) occurred in 5.15%. CONCLUSION: The predomination of different clones of HA-MRSA in the particular years was observed. In 1991, the EMRSA-10 (Hannover) clone predominated (53.3%). The Brasilian-Hungarian (EMRSA-1, -4, -11) clone predominated in 1994 (50%) as well as from 2005 to 2007 (41.3%), whereas in 1996 the Iberian clone was most frequent (53.9%).

Trends in antifungal susceptibility of Candida species--one year observation.

In the past years opportunistic fungal infections have seriously increased, mainly in immunocompromised patients. The aim of the study was to determine the prevalence of yeast-like fungi in invasive candidiasis and to estimate its susceptibility to chosen antifungal agents. One hundred and sixty strains of yeast-like fungi were cultured from various clinical material: samples from lower respiratory tract, blood, the peritoneal cavity and others. The susceptibility tests were established according to the quantitative E-test method. The Candida genus represented the main etiological factor of invasive candidiasis. The predominant species were: C. glabrata (71/160), C. albicans (34/160), C. krusei (17/160), C. tropicalis (14/160). All tested strains were the most resistant to itraconazole. Candida glabrata presented the 100% susceptibility to amphotericin B and caspofungin and was the least susceptible to itraconazole, posaconazole and voriconazole. Candida albicans was the most susceptible species to all antymicotics.

Polymerase chain reaction melting profiles of Candida glabrata clinical isolates in solid organ transplant recipients in comparison to the other group of surgical patients.

The aim of the retrospective study were to estimate the prevalence of Candida glabrata in liver and kidney transplant recipients compared to patients with short bowel syndrome receiving chronic total parenteral nutrition and relevance of the polymerase chain reaction melting profile (PCR MP) method for Candida glabrata strains differentiation. C. glabrata clinical strains isolated from patients were identified by using standard mycological procedures. The analysis of genetic relatedness of the isolated strains was conducted using the PCR MP method. The prevalence of C. glabrata comprised 29% of all episodes of fungal colonization and infection in solid organ transplant recipients, and 54% of those in hospitalized patients receiving long-term total parenteral nutrition. Among 78 isolates obtained from 55 solid organ transplant recipients and 2 organ donors, 44 different C. glabrata PCR MP fingerprints were observed. Forty-seven organ recipients and one organ donor carried unique C. glabrata strains. Among 37 isolates obtained from 31 patients receiving long-term TPN, 8 different PCR MP profiles of C. glabrata strains were observed. Two patients carried unique C. glabrata strains. Most of the C. glabrata colonization and infections in solid-organ transplant recipients were caused by endogenic strains. Most of the C. glabrata colonization and infections in hospitalized patients receiving long-term total parenteral nutrition could result by patient-to-patient transmission. The results showed that the PCR MP technique is a good discriminatory method for genotyping for C. glabrata strains.

Candida albicans morphologies revealed by scanning electron microscopy analysis

Scanning electron microscope (SEM) observations were used to analyze particular morphologies of Candida albicans clinical isolate (strain 82) and mutants defective in hyphae-promoting genes EFG1 (strain HLC52) and/ or CPH1 (strains HLC54 and Can16). Transcription factors Efg1 and Cph1 play role in regulating filamentation and adhesion of C. albicans' morphologies. Comparative analysis of such mutants and clinical isolate showed that Efg1 is required for human serum-induced cell growth and morphological switching. In the study, distinct differences between ultrastructural patterns of clinical strain's and null mutants' morphologies were observed (spherical vs tube-like blastoconidia, or solid and fragile constricted septa vs only the latter observed in strains with EFG1 deleted). In addition, wild type strain displayed smooth colonies of cells in comparison to mutants which exhibited wrinkled phenotype. It was observed that blastoconidia of clinical strain exhibited either polarly or randomly located budding. Contrariwise, morphotypes of mutants showed either multiple polar budding or a centrally located single bud scar (mother-daughter cell junction) distinguishing tube-like yeast/ pseudohyphal growth (the length-to-width ratios larger than 1.5). In their planktonic form of growth, blastoconidia of clinical bloodstream isolate formed constitutively true hyphae under undiluted human serum inducing conditions. It was found that true hyphae are essential elements for developing structural integrity of conglomerate, as mutants displaying defects in their flocculation and conglomerate-forming abilities in serum. While filamentation is an important virulence trait in C. albicans the true hyphae are the morphologies which may be expected to play a role in bloodstream infections.

Candida albicans morphologies revealed by scanning electron microscopy analysis.

Scanning electron microscope (SEM) observations were used to analyze particular morphologies of Candida albicans clinical isolate (strain 82) and mutants defective in hyphae-promoting genes EFG1 (strain HLC52) and/or CPH1 (strains HLC54 and Can16). Transcription factors Efg1 and Cph1 play role in regulating filamentation and adhesion of C. albicans' morphologies. Comparative analysis of such mutants and clinical isolate showed that Efg1 is required for human serum-induced cell growth and morphological switching. In the study, distinct differences between ultrastructural patterns of clinical strain's and null mutants' morphologies were observed (spherical vs tube-like blastoconidia, or solid and fragile constricted septa vs only the latter observed in strains with EFG1 deleted). In addition, wild type strain displayed smooth colonies of cells in comparison to mutants which exhibited wrinkled phenotype. It was observed that blastoconidia of clinical strain exhibited either polarly or randomly located budding. Contrariwise, morphotypes of mutants showed either multiple polar budding or a centrally located single bud scar (mother-daughter cell junction) distinguishing tube-like yeast/pseudohyphal growth (the length-to-width ratios larger than 1.5). In their planktonic form of growth, blastoconidia of clinical bloodstream isolate formed constitutively true hyphae under undiluted human serum inducing conditions. It was found that true hyphae are essential elements for developing structural integrity of conglomerate, as mutants displaying defects in their flocculation and conglomerate-forming abilities in serum. While filamentation is an important virulence trait in C. albicans the true hyphae are the morphologies which may be expected to play a role in bloodstream infections.

Acinetobacter baumannii multidrug-resistant strain occurrence in liver recipients with reference to other high-risk groups.

INTRODUCTION: The increasing clinical significance of Acinetobacter baumannii species is due to its ability to survive in hospital environments, its species-specific multidrug resistance, and its ability to instantly develop various drug-resistance mechanisms through antibiotic pressure. MATERIALS AND METHODS: We identified 16 A baumannii strains isolated from patients presenting postoperative infections in 2010. A baumannii isolates were obtained from clinical specimens by standard microbiologic methods. As previously described, we performed polymerase chain reaction (PCR) analysis for carbapenemase-encoding genes (VIM, IMP, SPM, OXA23, OXA24, OXA51, OXA58) in Acinetobacter spp. RESULTS: The double-disk synergy test phenotypic method did not detect any A baumannii strains producing metallo-beta-lactamaus cultured from swabs from all the patient groups. No products of PCR amplification with specific starters for VIM, IMP, and SPM (Sao Paulo metallo-ß-lactamase) genes were found. All analyzed strains were colistin-sensitive. Among five strains from liver recipients, one was imipenem- and meropenem-resistant. Four among six strains isolated from cancer patients were resistant to imipenem and/or meropenem; 1/5 were imipenem-and meropenem-resistant; 1, meropenem-resistant and imipenem-sensitive; 1, meropenem- and imipenem-resistant; and 1 with intermediate resistance to both meropenem and imipenem among swabs cultured from patients with postoperative complication after bone fracture. Fifteen among 16 analyzed A baumannii strains had an OXA51 gene. Two among five A baumannii strains isolated in liver recipients had only an OXA51 gene; one, OXA51 and OXA24 genes; one, OXA51 and OXA23 genes.

The probability of the Acinetobacter baumannii strain clonal spreading in donor-recipient systems, as confirmed by the molecular analysis of randomly amplified polymorphic DNA.

Acinetobacter baumannii is an important pathogen widely distributed in the hospital environment and responsible for a variety of nosocomial infections. This micro-organism especially affects patients with impaired host defenses in the intensive care unit. It has been implicated in severe nosocomial infections including bloodstream infections, pneumonia, and meningitides. Those infections are often outbreaks caused by a single clone spreading. The aim of our study was an epidemiological analysis of Acinetobacter baumannii strains isolated from hospitalized liver/kidney transplant donors and recipients. The analyzed material for epidemiological test included 13 A. baumannii strains isolated in 2010 from eight liver/kidney donors and 5 organ recipients. The epidemiological analysis of the isolates was performed by the use of the random amplified polymorphic DNA (RAPD)-polymerase chain reaction method to determine their genetic relatedness. We isolated 9 A. baumannii strains from 8 organ donors. Among this group of isolates, four strains showed the same fingerprints that were classified as one RAPD type 1. The remaining donor isolates revealed differentiated patterns. All strains isolated from recipients formed distinct RAPD types, one of which was identical to the group of four donor strains (RAPD type 1). The clonal spreading of A. baumannii strains was not observed among recipients but we noted a single case of probable transmission of the pathogen from the donor to the recipient.

Comparison of bacteria isolated from urinary tract infections in patients on transplant versus urologic wards.

OBJECTIVE: Urinary tract infections (UTI) are the most common hospital infections. Complications include sepsis and shock. Immunosuppressed transplant surgery patients may experience loss of the graft due to UTI. The purpose of this study was to determine the main microorganisms responsible for UTIs among patients of transplant wards compared to urologic wards. Additionally, drug susceptibility profiles of the most frequent microorganisms were analyzed. MATERIALS AND METHODS: We analyzed the results of positive urine cultures from patients on 2 transplant versus 1 urologic ward in 2010. RESULTS: The most common pathogen in urine samples from all 3 wards was Escherichia coli. Often, other Gram-negative bacilli of the genus Klebsiella spp, were cultured as well as Gram-positive cocci (Enterococcus spp). Yeasts of the genus Candida were only found in urine of patients of transplant wards. The percentage of resistant bacteria was much higher among bacteria from transplant patients. CONCLUSIONS: The high level of antimicrobial resistance of microorganisms isolated from the urine of transplant patients and the relatively high incidence of fungal infections, demand an especially quick, accurate microbiological diagnosis for this group of patients.

Differences in proteolytic activity and gene profiles of fungal strains isolated from the total parenteral nutrition patients.

Fungal infections constitute a serious clinical problem in the group of patients receiving total parenteral nutrition. The majority of species isolated from infections of the total parenteral nutrition patients belong to Candida genus. The most important factors of Candida spp. virulence are the phenomenon of "phenotypic switching," adhesins, dimorphism of fungal cells and the secretion of hydrolytic enzymes such as proteinases and lipases, including aspartyl proteinases. We determined the proteolytic activity of yeast-like fungal strains cultured from the clinical materials of patients receiving total parenteral nutrition and detected genes encoding aspartyl proteinases in predominant species Candida glabrata--YPS2, YPS4, and YPS6, and Candida albicans--SAP1-3, SAP4, SAP5, and SAP6. C. albicans released proteinases on the various activity levels. All C. glabrata strains obtained from the clinical materials of examined and control groups exhibited secretion of the proteinases. All 13 isolates of C. albicans possessed genes SAP1-3. Gene SAP4 was detected in genome of 11 C. albicans strains, SAP5 in 6, and SAP6 in 11. Twenty-six among 31 of C. glabrata isolates contained YPS2 gene, 21 the YPS4 gene, and 28 the YPS6 gene. We observed that clinical isolates of C. albicans and C. glabrata differed in SAPs and YPSs gene profiles, respectively, and displayed differentiated proteolytic activity. We suppose that different sets of aspartyl proteinases genes as well as various proteinase-activity levels would have the influence on strains virulence.

Algorithm of clinical protocol lowering the risk of systemic Mycosis infections in allografts recipients.

The aim of the study was to describe a diagnostic protocol to lower the risk of a mycotic invasive infection among allotransplant recipients and to suggest the use of preoperative prophylaxis and/or empiric therapy. We chose a group of 268 allograft recipients with transient or constant yeast colonization or confirmed yeast infection. Among 7744 clinical samples, 475 were positive for fungi. We used conventional fungal laboratory diagnosis, enzymatic activity tests, serologic tests, molecular diagnosis of samples from sterile body sites, and histopathologic examinations. The following clinical samples were examined: blood samples; swabs from mouth lesions, throat, and rectum; and sputum, urine, and fecal samples from kidney transplant recipients and simultaneous pancreas-kidney transplantation recipients who are highly predisposed to mycotic infections. We established microbiologic criteria of a systemic mycosis and principles to distinguish colonization from infection.

Trichosporon asahii as a prospective pathogen in solid organ transplant recipients.

Trichosporon spp. is not an important factor of mycotic infections in immunocompetent patients. It may be a cause of invasive mycoses with a high mortality rate in patients undergoing solid organ transplantation. We have analysed the antifungal agents' susceptibility of Trichosporon asahii and its frequency of occurrence as a prospective etiological agent of infections in liver, kidney and simultaneous pancreas-kidney transplant recipients. Clinical specimens (urine, blood, peritoneal fluid and swabs) were obtained from patients hospitalised in the Institute of Transplantation Medicine, Department of General and Transplantation Surgery, Medical University of Warsaw in 2005 and 2006. Microbiological tests were performed in Mycological Laboratory, Department of Microbiology, Medical University of Warsaw. A total of 475 strains of yeast-like fungi were isolated from clinical specimens taken from 263 liver, kidney and simultaneous pancreas-kidney transplant recipients and from 26 organ donors. Trichosporon asahii was found in 26 clinical samples taken from 18 patients and one organ donor. Positive cultures were obtained from 22 urine samples, one stoma fluid, one wound swab, one tracheal aspirate and one ejaculate. Isolates of Trichosporon asahii were found in 6% of total positive mycological cultures in the solid organ transplant recipients. Among cultured strains, 11 isolates were resistant to fluconazole, four to itraconazole and three of them demonstrated resistance to amphotericin B.

Surgical site infections in liver recipients in the early posttransplantation period: etiological agents and susceptibility profiles.

OBJECTIVE: This study evaluated the frequency of microbial isolates and their susceptibility profiles from cultures at the surgical site of 83 liver recipients in the early posttransplantation period. PATIENTS AND METHODS: We prospectively collected microbiologic culture data on 83 adult patients undergoing orthotopic liver transplantation (OLT) using standard procedures and commercially available tests. Susceptibility of the strains to antibacterial agents was performed by the Clinical and Laboratory Standards Institute (CLSI) guidelines. RESULTS: All patients were followed prospectively for the first 4 weeks after surgery. Among 284 microbial isolates from clinical surgical site samples in 80 liver recipients, cultures were positive in 110 samples. The most commonly isolated species were: Gram-positive cocci (n = 222 isolates, 78%) with dominance of methicillin-resistant coagulase-negative staphylococci (MRCNS; 42%) and high-level aminoglycoside-resistant enterococci (HLAR strains; 24.3%). Gram-negative bacteria were identified in 21.5% of positive cultures, including 30 strains (24%) from the Enterobacteriaceae family, with 13.3% of extended spectrum beta-lactamase producers [ESBL(+)]. Significant differences (P = .0012) were observed during the analysis of changes in the occurrence of Gram-positive bacteria isolated from the surgical site in the first week versus the second to the end of the fourth week. CONCLUSION: Gram-positive bacteria predominated as 78% of isolates.

Bacteria isolated from bile samples of liver recipients in the early period after transplantation: epidemiology and susceptibility of the bacterial strains.

OBJECTIVE: We estimated the frequency and susceptibility to antibacterial agents of bacterial isolates from bile samples obtained from 83 liver recipients in the early period after transplantation. PATIENTS AND METHODS: We prospectively collected data on 83 adult patients undergoing orthotopic liver transplantation (OLT), including bile samples taken during the first 30 days after OLT from adult liver recipients suspected to have bile infections. The isolation/identification of cultured bacteria was performed according to standard microbiological procedures and commercially available tests. Susceptibility of the strains to antibacterial agents was determined according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. RESULTS: Among 210 bile samples obtained from 79 liver recipients, bacterial cultures were positive in 110 samples from 59 (75%) recipients yielding 156 bacterial strains. The most commonly isolated species were as follows: gram-positive cocci (109 isolates) with dominance of coagulase-negative staphylococci (52%) and enterococci (36%); and gram-negative bacteria, 21 strains from the Enterobacteriaceae family and 14 of non-fermenting rods. We identified some multidrug-resistant (MDR) bacterial strains. In the first week after OLT, we investigated samples from 59 patients, yielding 36 bacterial strains. From the second to the end of the fourth week after OLT, 120 bacterial strains were isolated from 65 recipients. CONCLUSION: Gram-positive bacteria comprised 68.5%. The dominance of MDR gram-positive bacteria may be related to selection by perioperative antibiotic prophylaxis.

Detection of Clostridium difficile in stool samples from patients in the early period after liver transplantation.

OBJECTIVE: We examined the frequency of detection of Clostridium difficile (CD) toxins compared with the recovery of C. difficile in stool specimen cultures among orthotopic liver transplant (OLT) patients with nosocomial diarrhea in the early period. MATERIALS AND METHODS: The study included stool samples obtained during the first 30 days after OLT in adults who were suspected of CD-associated diseases. The identification of cultured CD strains was performed by standard microbiological methods. The presence of CD toxins was assayed using a commercial immunoassay. RESULTS: All patients were followed prospectively for CD infections from the date of OLT for the first 4 weeks after surgery. Among 54 samples, 16.7% were culture-positive for CD. CD toxins were tested on 54 samples, yielding 63% toxin-positive samples and 30% toxin- and culture-negative results. In the first week after OLT, samples from 19 patients were subjected to CD investigation. Among 19 samples positive for toxin, 52.6% of all samples were culture-negative. We analyzed 35 samples from the second to the fourth week after OLT in 31 recipients. Among 35 samples, 68.6% and 25.7% were positive for CD toxin and for culture, while 20% of samples were negative for toxin and culture. CONCLUSION: In our study, 63% of samples were toxin-positive with 16.7% yielding growth of CD and 30% being negative for toxins and cultures.

Etiological agents of bacteremia in the early period after liver transplantation.

Bacteremia is one of the major infections in orthotopic liver transplantation (OLT). The study of 83 adults who underwent OLT from 2001 to 2004, included patients followed prospectively from the day of transplantation to 4 weeks after the procedure by bacteriological cultures. The microorganisms were investigated according to standard National Committee for Clinical Laboratory Standards (NCCLS) procedures. Blood samples were examined in 59 recipients (71.1%) before and in 76 patients (91.6%) during the month after transplantation. Among 249 investigated samples, 96 were positive, as cultured from 19 recipients before OLT and 48 patients afterward. The most common were Gram-positive cocci (n = 71) and coagulase-negative staphylococci (n = 52), including methicillin-resistant coagulase-negative staphylococci (MRCNS). Enterococcus spp. occurred in 9 isolates (high-level aminoglycoside-resistant enterococci [HLAR] strains were cultured). We cultured the Enterobacteriaceae family (n = 16 isolates) and (n = 15 isolates), Gram-negative nonfermenting rods some of which were extended spectrum beta-lactamase producing [ESBL(+)] strains. The predominance of Gram-positive cocci was caused by CNS, and the use of prophylaxis to reduce Gram-negative bacteria. The increased rate of isolation of bacteria with multidrug resistance (MDR) to antimicrobial agents may be due to their frequent use for prophylaxis of bacterial infections in OLT. These MDR bacterial strains caused severe BSI after OLT.