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Objective Pseudomonas aeruginosa is the most important cause of lung infection among cystic fibrosis (CF) patients, and to reduce the severity of the infection, facility-specific cumulative antibiograms could help clinicians in empirical treatment. Methods Respiratory samples of CF patients between January 2015 and December 2018 were scanned through Laboratory Operating System retrospectively. Demographical data of patients, culture results, and antibiotic susceptibilities are recorded using Microsoft Excel 2010. Cumulative antibiogram data were obtained according to the CLSI M39A4 document. Results The number of registered patients increased in 4 years from 154 to 253. The mean age of patients varied from 9 to 11.7 (range, 2–42). The ratio of patients with a positive culture for P. aeruginosa increased from 32 to 40%, and the mean patients' age decreased from 16.6 to 11.1 (p Conclusion Antimicrobial resistance is a challenging problem in CF patients, and surveillance should be done regularly.

To the Editor, Serology may offer valuable information during COVID-19 pandemic; however, published papers mainly reported the results of symptomatic patients having positive RT-PCR on upper respiratory tract specimens [1]. More studies are needed to address whether asymptomatic patients, or patients with chest imaging compatible with COVID-19 but negative RT-PCR, have different antibody response that could influence assays performances. We wanted to share our data from Turkey where 4,323,596 COVID-19 cases were detected out of 44,087,628 PCR tests by April 20, 2021 but there are only a couple of published studies about serodiagnosis of the infection.The authors have no funding source for the study. The authors have no conflicts of interest to declare.

Objective: We aimed to analyse the positivity rate and cycle threshold values indicating viral loads for SARS CoV-2 among different respiratory specimens and also to evaluate the diagnostic efficacy of saliva samples Materials and Methods: We included combined oropharyngeal and nasopharyngeal swab (cONS), sputum, and tracheal aspirate (TA) specimens of patients Unpreserved saliva samples were collected prospectively from hospitalized patients within 72 hours of admission SARS CoV-2 RNA was extracted by using Bio-Speedy viral nucleic acid buffer than RT-PCR was performed with Bio-Speedy COVID-19 qPCR detection kit Results: Retrospective evaluation revealed SARS CoV-2 RNA in 19 66% of cONS (n: 5819), 30 77% of sputum (n: 39), 29 41% of TA samples (n: 34) from 4812 patients In the majority (86 72%) of the samples, the first cONS sample was positive Consecutive cONS and sputum/TA samples were investigated in 52 patients of whom 11 were positive with either of these samples Saliva positivity was detected in 60% of cONS positive (n: 20) and 30% of cONS negative (n: 12) patients Conclusion: Although, cONS samples show the greatest diagnostic guidance, repeated sampling from multiple sites of the respiratory tract increases the possibility of COVID-19 diagnosis Saliva samples might be considered as an alternative specimen © 2021 Marmara University Press, All Rights Reserved

Highlights • There are limited number of studies analyzing viral load in COVID19 patients and any data that compare viral load to chest computerized tomography (CT) severity. • There are limited number of studies that give the amount of SARS-CoV-2 RNA in clinical specimens by reporting cycle threshold (Ct) value for RT-PCR. • The total stress score (TSS) was suggested to quantify pulmonary inflammation and correlate to the clinical classifications. TSS is a quantification method to score the severity of inflammation on CT images based on summing up degree of acute lung inflammation lesions involvement of each lobe (including ground-glass opacity or consolidation or other fuzzy interstitial opacities). • To our knowledge, this is the first study that analyse TSS of chest CT and Ct values of SARS-CoV-2 RNA in both hospitalised and outpatients., Aim There are limited number of studies analyzing viral load in COVID19 patients and any data that compare viral load to chest computerized tomography (CT) severity. This study aims to evaluate the severity of chest CT in reverse transcriptase polymerase chain reaction (RT-PCR) positive patients and factors associated with it. Methodology SARS-CoV-2 RNA was extracted from nasopharyngeal swab samples by using Bio-speedy viral nucleic acid buffer. RT-PCR test was performed with primers and probes targeting the RdRp gene (Bioexen LTD, Turkey) and results were quantified as Cycle threshold (Ct) values. Chest CT of SARS-CoV-2 RNA positive patients (n: 730) in a period between March 22 and May 20, 2020 were evaluated. Total severity score (TSS) of chest CT ranged 0-20 was calculated by summing up degree of acute lung inflammation lesions involvement of each of the five lung lobes. Results Out of the 284 patients that were hospitalized, 27 (9.5%) of them died. In a total of 236 (32.3%) patients, there were no findings in CT and 216 (91.5%) of them were outpatients (median age 35). TSS was significantly higher in hospitalized patients although only 5.3% had severe changes. Ct values were lower among outpatients indicating higher viral load. An inverse relation between viral load and TSS was detected in both groups. CT severity was related with age and older patients had higher TSS (p

Introduction: The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19). First COVID-19 case was detected in March, 10, 2020 in Turkey and as of May, 18, 2020 148,067 cases have been identified and 4096 citizens have died. Tuberculosis (TB) is a worldwide public health concern, incidence of tuberculosis (per 100,000 people) in Turkey was reported at 14, 1 in 2018. During pandemic COVID-19 was the main concern in every clinic and as we discuss here overlapping respiratory diseases may result in delaying of the diagnosis and treatment. Methodology: There were 4605 respiratory samples examined between March 23 and May 18 for COVID-19 and 185 samples for Mycobacterium tuberculosis in our laboratory. The Xpert Ultra assay was performed for the diagnosis of pulmonary tuberculosis; SARS-CoV-2 RNA was determined by real-time PCR (RT-PCR) analysis in combined nasopharyngeal and deep oropharyngeal swabs of suspected cases of COVID-19. Results: Both of SARS-CoV-2 and M. tuberculosis tests were requested on the clinical and radiological grounds in 30 patients. Here we discussed 2 patients who were both COVID-19 and TB positive. One patient already diagnosed with tuberculosis become COVID-19 positive during hospitalization and another patient suspected and treated for COVID-19 received the final diagnosis of pulmonary TB and Human Immunodeficiency Virus infection. Conclusions: We want to emphasize that while considering COVID-19 primarily during these pandemic days, we should not forget one of the “great imitators”, tuberculosis within differential diagnoses.

Background Chronic pulmonary infection is the leading cause of mortality and morbidity in patients with cystic fibrosis (CF). The most common pathogens isolated in CF are Staphylococcus aureus (SA) and Pseudomonas aeruginosa (PA). Chronic infection of PA and methicillin-resistant S. aureus (MRSA) are associated with worse survival and antibiotic eradication treatment is recommended for both. This study compared the outcomes between intravenous (IV) and non-IV antibiotics in eradication of PA and MRSA. Methods This was a single-center retrospective study. All respiratory specimen cultures of 309 CF patients and eradication regimens between 2015 and 2019 were reviewed. Patients received eradication treatment in case of first ever isolation or new isolation after being infection-free >= 1 year. The primary analysis was the comparison of the percentage of successful eradication after receiving IV and non-IV eradication regimens. Demographic and clinical risk factors for eradication failure were also analyzed. Results One hundred and two patients with PA isolations and 48 patients with MRSA were analyzed. At 1 year, 21.6% in PA group and 35.4% in MRSA group were successfully eradicated. There was not any statistically significant difference between IV versus non-IV antibiotic regimens on eradication in either group. Additionally, none of the clinical risk factors was significantly associated with eradication failure in PA and MRSA groups. Conclusion In the eradication of PA and MRSA, IV and non-IV treatment regimens did not show any superiority to one another. Non-parenteral eradication could be a better option considering the cost-effectiveness and the treatment burden of IV treatments due to hospitalization and the need for IV access.

Background. COVID-19 infection may have multiorgan effects in addition to effects on the lungs and immune system. Recently, studies have found thyroid function abnormalities in COVID-19 cases which were interpreted as euthyroid sick syndrome (ESS) or destructive thyroiditis. Therefore, in this study, we aimed to evaluate the thyroid function status and thyroid autoimmunity in COVID-19 patients. Material and Method. 205 patients were included. The medical history and laboratory parameters at admission were collected from medical records. Serum thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroid peroxidase antibody, and thyroglobulin antibody were measured, and patients were classified according to thyroid function status. Results. 34.1% of the patients were euthyroid. Length of hospitalization ( p < 0.001 ), rate of oxygen demand ( p < 0.001 ), and intensive care unit (ICU) admission ( p = 0.022 ) were lower, and none of the euthyroid patients died. 108 (52.6%) patients were classified to have ESS, 57 were classified as mild, and 51 were moderate. The inflammatory parameters were higher in patients with moderate ESS. In cluster analysis, a high-risk group with a lower median FT3 value (median = 2.34 ng/L; IQR = 0.86), a higher median FT4 value (median = 1.04 ng/dL; IQR = 0.33), and a lower median TSH value (median = 0.62 mIU/L; IQR = 0.59) included 8 of 9 died patients and 25 of the 31 patients that were admitted to ICU. Discussion. Length of hospitalization, oxygen demand, ICU admission, and mortality were lower in euthyroid patients. Moreover, none of the euthyroid patients died. In conclusion, evaluation of thyroid function tests during COVID-19 infection may give information about the prognosis of disease.

BackgroundCoronavirus disease 2019 (COVID-19) quickly spread worldwide to become a pandemic. This study aimed to define the predictors of critical illness development within 28 days postadmission.MethodsWe conducted a prospective cohort study including 477 PCR-positive COVID-19 patients admitted to a tertiary care hospital in Istanbul from March 12 to May 12, 2020. The development of critical illness, e.g., invasive mechanical ventilation and/or death, was followed for a period of 28 days postadmission. Demographic characteristics, number of comorbidities, illness severity at admission defined by the WHO scale, vital signs, laboratory findings and period of admission to the hospital were independent variables. Cox proportional hazards analysis was performed, and the C-index was calculated.ResultsThe median (IQR) age of the cohort was 55.0 (44.0-67.0) years, and 50.1% were male. The most common presenting symptoms were cough, dyspnea and fatigue. Overall, 65.2% of the patients had at least one comorbidity. Hydroxychloroquine was given to 99.2% of the patients. Critical illness developed in 45 (9.4%; 95% CI: 7.0%-12.4%) patients. In the multivariable analysis, age (HR: 1.05, pConclusionsAge, comorbidity number, WHO scale, LDH and procalcitonin were independently associated with critical illness development. Mortality from COVID-19 seems to be decreasing as the pandemic advances.summaryWe analyzed 477 confirmed COVID-19 patients for the development of critical illness, e.g., invasive mechanical ventilation and/or death within 28 days postadmission. Age, comorbidity number, WHO scale, LDH and procalcitonin were independently associated with critical illness development.

Background This study aimed to reveal the differences between coronavirus disease 2019 (COVID-19) infections and non-COVID-19 respiratory tract infections in pediatric patients. Methods Sixty pediatric patients admitted to the hospital between March 11, 2020 and April 15, 2020 with respiratory tract infections were evaluated retrospectively. Among them, 20 patients with reverse transcription-polymerase chain reaction (RT-PCR) tests and chest computed tomography (CT) examinations were included in the study. According to the RT-PCR test results, the patients were divided into the COVID-19 and non-COVID-19 groups. The clinical observations, laboratory results, and radiological features from the two groups were then compared. Results According to the RT-PCR test results, 12 patients were assigned to the COVID-19 group and 8 to the non-COVID-19 group. There were no significant differences between the two groups in terms of clinical or laboratory features. In terms of radiological features, the presence of bronchiectasis and peribronchial thickening was statistically significantly higher in the non-COVID-19 group (P = 0.010 and P = 0.010, respectively). Conclusions In pediatric cases, diagnosing COVID-19 using radiological imaging methods plays an important role in determining the correct treatment approach by eliminating the possibility of other infections.

Background: We aimed to determine hand hygiene (HH) compliance of the healthcare workers (HCW’s) and evaluate if there is an epidemiological relation between the microorganisms isolated from the hands of HCWs and patients clinical materials in the neonatal intensive care unit (NICU).Methods: HH compliance was observed in two unannounced phases in March and in August within the scope of 5 indications determined by WHO. Between two phases personnel was trained to improve HH by educational sessions and introduction of Semmelweis system hand in scan (HIS, Sysmex) in the unit. A total of 22 nurses, 11 physicians and 5 staff was working in the NICU. Hand samples taken from HCW by glove juice method were inoculated quantitatively in culture plates and colonies were identified by MALDI-TOF MS. Epidemiological relation between clinical isolates and hand samples was investigated with arbitrary primed PCR.Results: Although overall compliance remained only 50%, a significant increase in compliance was detected in August prior to aseptic procedures and after contact with patients and body fluids. Alcohol scrub was preferred as 60.4% in March and 75.2% in August. HH efficacy reached to 72% by implementing HIS. During this period, 10.7% of 607 patient’s samples revealed clinically significant growth. Potential pathogens were isolated in 5.2% of 144 hand samples, but any epidemiological correlation with patient isolates was detected.Conclusions: HH compliance observations should be done at regular intervals and current technology could be utilized in trainings to overcome hospital related infections.

Objective To investigate the effects of plant-derived phenolic compounds ( i.e. caffeic acid, cinnamic acid, ferulic acid and vanillic acid) on the production of quorum sensing regulated virulence factors such as pyocyanin, biofilm formation and swarming motility of Pseudomonas aeruginosa ( P. aeruginosa ) isolates. Methods Fourteen clinical P. aeruginosa isolates obtained from urine samples and P. aeruginosa PA01 strain were included in the study. The antibacterial effects of phenolic compounds were screened by well diffusion assay. Pyocyanin and biofilm activity were measured from culture supernatants and the absorbance values were measured using a spectrophotometer. Swarming plates supplemented with phenolic acids were point inoculated with P. aeruginosa strains and the ability to swarm was determined by measuring the distance of swarming from the central inoculation site. Results Tested phenolic compounds reduced the production of pyocyanin and biofilm formation without affecting growth compared to untreated cultures. Moreover, these compounds blocked about 50% of biofilm production and swarming motility in P. aeruginosa isolates. Conclusions We may suggest that if swarming and consecutive biofilm formation could be inhibited by the natural products as shown in our study, the bacteria could not attach to the surfaces and produce chronic infections. Antimicrobials and natural products could be combined and the dosage of antimicrobials could be reduced to overcome antimicrobial resistance and drug side effects.

Introduction: In the opportunistic pathogen Pseudomonas aeruginosa , the production of several virulence factors depends on quorum sensing (QS) involving N -acylhomoserine lactone signal molecules. In vitro studies have suggested that the QS system is crucial in the pathogenesis of P. aeruginosa . However, it is unclear whether QS systems of P. aeruginosa play the same role during infections. Methodology: In this study, to explore the contribution of QS systems to the pathogenesis of P. aeruginosa during urinary tract infections, we collected 82 clinical isolates. Detection of N -acyl-homoserine lactones (C12-HSL and C4-HSL) was performed on agar plates employing biosensor strains C. violaceum . Elastase and biofilm production were determined spectrophotometrically. QS genes were detected by PCR and subsequently underwent sequencing. Results and conclusion: Six isolates were found to be negative in the production of both C12-HSL and C4-HSL and all virulence factors tested. PCR analysis of these isolates revealed that four isolates contained all four QS genes while one isolate was negative for lasR gene, and one isolate negative for lasI, lasR and rhlR genes. Sequence analyses of these isolates showed that the lasR, lasI, rhlR and rhlI genes had point mutations. The combination of these mutations probably explains their C12-HSL, C4-HSL and virulence factor deficiencies. Results of this study suggest that QS deficient clinical isolates occur and are still capable of causing clinical infections in humans.

A high rate (48.6%) of extended spectrum beta-lactamase production among Klebsiella pneumoniae (ESBL-KP) clinical isolates in the paediatric wards of our hospital prompted the introduction of enhanced infection control measures, and after the implementation of these measures, we instituted a prospective surveillance programme, with a nested case-control study to determine the risk factors for rectal colonisation by ESBL-KP.Over a 1-year period, rectal swabs from patients and samples from the environment and the hands of health-care workers were cultured. Strain typing of ESBL-KP isolates was performed using pulsed-field gel electrophoresis. Characteristics of patients who were colonised with ESBL-KP during hospital stay were compared with those of patients who remained negative for ESBL-KP. Multivariate analysis was performed with model-building using stepwise logistic regression to determine independent risk factors for ESBL-KP acquisition.Forty (18.5%) of 216 patients became colonised with ESBL-KP. The strongest independent predictors of ESBL-KP colonisation were mechanical ventilation (odds ratio (OR): 4.28) and hospitalisation for longer than 14 days (OR: 6.97). Genotyping of the isolates indicated probable patient-to-patient transmission; however, we could not determine the route of this spread. During the study period, a 1.6% rate of ESBL-KP clinical infection per 500 patient admissions was observed, in contrast to a 7% rate in the previous year.Prolonged length of stay and mechanical ventilation were independent predictors of ESBL-KP colonisation. Enhanced infection control measures, antimicrobial stewardship and screening for rectal carriage were associated with a substantial decrease in paediatric units.

Background: An absence of Haemophilus influenzae type b (Hib) disease surveillance and epidemiological data on the pharyngeal carriage of Turkish children causes delay in the introduction of conjugated Hib vaccination into proposed national vaccination programs. Methods: Oropharyngeal cultures were obtained from 1404 healthy infants and children. Six healthy child clinic (HCC), 11 day-care centers (DCC) and seven elementary schools (ES) were randomly selected in seven different counties at the Anatolian side of Istanbul between January and April 2000. Results: Haemophilus influenzae was isolated from 315 (22.8%) of all participants and 98 (31%) isolates were serotype b. The carriage rate for Hib was higher in children at DCC (43 out of 448, 9.6%) and ES (46 out of 504, 9.1%) compared to infants 0−24 months of age (nine out of 430, 2.1%) presented to HCC. All Hib isolates were susceptible to azithromycin, chloramphenicol and cefotaxime. Beta-lactamase production was detected in only one isolate. Trimethoprim-sulfamethoxazole resistance was found in 8.5% of Hib isolates. Multivariate analysis showed that DCC and ES attendance were independent predictors of Hib carriage. Conclusion: A significant proportion of healthy Turkish children was shown to be colonized with Hib. The burden of invasive Hib infections should be determined in order to evaluate the Hib conjugated vaccine as a part of a routine immunization program in Turkey.

Meningococcal disease is one of the most important causes of morbidity and mortality among children in many parts of the world. Main reservoir of carriage and site of meningococcal dissemination appears to be the upper respiratory tract. Colonization of Neisseria meningitidis and lactamica and factors affecting this carriage were determined in a group of healthy children aged 0–10 years. Meningococcus and N. lactamica carriage were detected in 17 (1.23%) and 245 (17.7%) of 1382 subjects, respectively. Number (%) of serogroups for meningococci was 1 (6), 5 (29), 0 (0), 1 (6), 1 (6), and 9 (53) for A, B, C, D, W135, and Y, respectively. Having more than three household members, elementary school attendance, pharyngeal carriage of Streptococcus pneumoniae and Haemophilus influenzae were associated with carriage of meningococci, whereas age less than 24-month was associated with carriage of N. lactamica. There was a reverse carriage rate between N. meningitidis and N. lactamica by age which may suggest a possible protective role of N. lactamica against meningococcal colonization among pre-school children.

Introduction: Staphylococcus aureus is one of the first bacteria colonizing in cystic fibrosis (CF) respiratory tract and different virulence factors are responsible for disease progression. It is not clear if CF S. aureus strains are more virulent than strains isolated from non-CF patients. Methodology: Biofilm production was detected by a modified tissue culture plate method, presence of genes encoding for Panton-Valentine leukocidin (PVL) was investigated by a signal amplified sandwich hybridization assay and antimicrobial susceptibility patterns were detected by disk diffusion method. Results: Staphylococcus aureus clinical isolates (n = 88) recovered from respiratory tract specimens in which 31 of them were from cystic fibrosis (CF) patients were analysed. Biofilm production was detected in 96.8% of CF isolates in which 32.3% exhibited strong positive phenotype and in 47.4% of non-CF isolates in which strong positive phenotype was not observed (p < 0.05). All CF isolates were methicillin susceptible, whereas 53.4% of non-CF isolates (n = 31) were methicillin resistant. No resistance was observed for vancomycin, chloramphenicol and trimethoprim/sulfamethoxazole in any of the isolates. PVL genes were detected only in two isolates (2.3%), one from each group, CF and non-CF, which both were methicillin susceptible Conclusion: Biofilm rather than PVL production appears to be an important virulence factor in CF patients.

We conducted three prospective studies of Haemophilus influenzae in different groups of children. Pharyngeal swab samples were taken (i) from 1382 healthy infants and children between 0 and 10 years of age (group 1), attending well child clinics (n=438), day care centres (n=440) and elementary schools (n=504), and (ii) from 322 children aged 2–10 years (group 2), clinically diagnosed as having upper respiratory tract infection. Pharyngeal swab samples and sinus aspirates were obtained from 49 children between 2 and 9 years of age (group 3), clinically diagnosed as having sinusitis. H. influenzae was isolated in similar rates from 315 (22.7%) of children in group 1, 72 (22.3%) of children in group 2 and 12 (24.4%) of children in group 3. Serotype b comprised 7, 5.2 and 2% of all H. influenzae isolates for group 1, 2 and 3, respectively. Production of β-lactamase was detected in 1.0% of H. influenzae type b isolates in group 1, 1.2 and 6.1% of all isolates in group 2 and 3, respectively. There were no β-lactamase negative ampicillin-resistant strains.

Background. Treatment of recent tuberculosis infection in children aged ! 2 years is essential, because of high risk of progression to disease, but diagnosis is hindered by the inaccuracy of the tuberculin skin test (TST). More-accurate T cell-based tests of infection could enhance diagnosis by optimizing interpretation of the TST results. Methods. A total of 979 child tuberculosis contacts in Istanbul underwent the TST and enzyme-linked immunospot assay. Using enzyme-linked immunospot test results as a reference standard, we assessed the effect of age and bacille Calmette-Guerin ( BCG) vaccination on the sensitivity and specificity of the TST, and we computed the optimal TST cutoff points, using receiver operating characteristic curves. Results. With a TST cutoff point of >= 10 mm, the sensitivity of the TST was 66% for children aged = 2 years, and overall accuracy was low for children with 1 BCG scar. Conclusions. Negative results of the TST cannot exclude tuberculosis infection for child tuberculosis contacts aged = 2 years, the accuracy of the TST can be improved by adjustment of cutoff points for BCG-vaccinated children but remains poor for children with >1 BCG scar. This methodology can define optimal TST cutoff points for diagnosis of tuberculosis infection tailored to target populations.

Pseudomonas aeruginosa infections are particularly common in people with cystic fibrosis and despite regular treatment with antibiotics, lung damage due to chronic infection with P. aeruginosa remains the major cause of death in those patients. In order to initiate an infection, P. aeruginosa needs contact with the respiratory epithelial surface and by means of its adhesins i.e., fimbria, hemagglutinins,etc., it recognizes and adheres to the corresponding epithelial receptors. We treated P. aeruginosa strains isolated from sputum of cystic fibrosis patients with several glycolipids such as sulfatide, sulfated ganglioside mixture (GM1a, GD1b, GT1b), asialo-GM1 and galactocerebrosides to determine their effect on attachment with pharyngeal epithelial cells. Sulfated ganglioside mixture and sulfatide inhibited the attachment of P. aeruginosa significantly, whereas asialo-GM1, Gal-Cer and sodium sulfite had no effect on attachment inhibition. This finding suggests that sulfated glycoconjugates found in the extracellular matrix, in mucus and on the surface of epithelial cells of human trachea and lung mediates attachment of P. aeruginosa.

Three virulence factors comprising proteinase, phospholipase, and biofilm among 68 Candida albicans and 31 non-albicans Candida strains (11 C. tropicalis, 8 C. parapsilosis, 6 C. glabrata, 4 C. guillermondii, 2 C. krusei) isolated from blood cultures were analyzed. In total, 61 (89.7%) C. albicans strains were detected as proteinase positive whereas eight (25.8%) non-albicans Candida strains were proteinase positive (P < 0.05). Phospholipase production was detected in 41 (60.3%) C. albicans strains. All non-albicans Candida strains were phospholipase negative. Biofilm production was determined by both visual and spectrophotometric methods. Eight (11.8%) of C. albicans strains and 13 (41.93%) of 31 non-albicans Candida strains were biofilm positive with two of the methods (P < 0.05). According to our results, we may suggest that detection of hydrolytic enzyme and biofilm production abilities of the Candida isolates in clinical mycology laboratories may warn the clinican for a possible hematogenous infection.

In order to determine the local epidemiology of candidemia, Candida strains isolated between 1994 and 2000 were identified to species level; antifungal resistance patterns and DNA fingerprints were analyzed. Identification of Candida strains (n: 140) was performed with germ tube test and carbohydrate assimilation reactions. Minimal inhibitory concentrations were determined using a commercial test for 5-flucytosine and the broth macrodilution method according to NCCLS for fluconazole and amphotericin B. Molecular relatedness was determined by restriction endonuclease analysis of genomic DNA followed by probe hybridization. C. albicans (37.2%), C. parapsilosis (32.2%), and C. tropicalis (12.2%) comprised 114 (81.4%) of 140 isolates. Susceptibility tests did not reveal resistance to amphotericin B in any of the Candida isolates. Fluconazole resistance was detected in one isolate of C. krusei, and 5-flucytosine resistance in two C. tropicalis isolates and one C. albicans isolate. Significantly higher frequency of clusters with identical strains in C. parapsilosis and C. tropicalis was detected compared to C. albicans. Pediatric wards are particularly important in the nosocomial transmission of non-albicans candida species.

During a 6-month period, swab samples were obtained from the nares, axilla and perineum of 1,000 children, age 0 to 16 years, who were attending a pediatric outpatient clinic. Staphylococcus aureus was isolated in 173 of the children. Only one child, a 35-day-old boy who had remained at the neonatal intensive care unit for 1 week after birth, was identified as a carrier of methicillin-resistant S. aureus. Except in diagnosed cases of allergic rhinitis, potential predisposing factors for colonization with S. aureus in our sample were comparable to those in non-colonized children.

Enterotoxigenic Bacteroides fragilis (ETBF) has been implicated in diarrhoeal illness in animals and humans. Recent data suggest that ETBF is associated with flares of inflammatory bowel disease. Toxigenicity is attributed to expression of a toxin referred to as fragilysin, which stimulates fluid accumulation in ligated intestinal segments and alter the morphology of human intestinal cells. Three different isoforms or variants of the enterotoxin gene, designated bft-1, bft-2, and bft-3, have been identified. In this study we investigated the distribution of bft alleles among ETBF strains in stool specimens from patients with colon cancer (n: 31), the control patients (n: 8) and extraintestinal sources (n: 15). We used restriction fragment length polymorphism analysis of the PCR-amplified enterotoxin gene and sequencing the PCR-product to detect the isoforms of bft gene. Among the stool strains, bft-1 was found to be more common than bft-2; as it was detected 27 of 31 strains from colon cancer patients and 7 of 8 control strains. The bft-1 isoform was also found in almost all isolates from extraintestinal sites. No bft-3 subtype was detected among all tested strains.

The prevalence of enterotoxigenic Bacteroides fragilis (ETBF) was investigated in stool specimens from 73 patients with colorectal cancer and from 59 control patients. Stool specimens were cultured on Bacteroides Bile Esculin agar and B. fragilis was identified by conventional methods. After DNA extraction, the enterotoxin gene (bft) was detected by PCR in 38% of the isolates from colorectal cancer patients, compared with 12% of the isolates from the control group (p 0.009). This is the first study demonstrating an increased prevalence of ETBF in colorectal cancer patients.

Pseudomonas aeruginosa is an opportunistic pathogen causing severe respiratory infections. The pathogenesis of these infections is multifactorial and the production of many virulence factors is regulated by quorum sensing (QS), a cell-to-cell communication mechanism. The two well defined QS systems in P. aeruginosa, the las and rhl systems, rely on N-acyl homoserine lactone signal molecules, also termed autoinducers. We assessed the activity of QS-dependent virulence factors (including elastase, alkaline protease, pyocyanin and biofilm production) in respiratory isolates of P. aeruginosa and their relationship with antimicrobial susceptibility. We identified sixteen isolates displaying impaired phenotypic activity; among them, eleven isolates were also defective in autoinducer production, and therefore considered QS-deficient. Six of the QS-deficient isolates failed to amplify one or more of the four QS regulatory genes (lasI, lasR, rhlI, rhlR) with PCR: one isolate was negative for rhlR, two isolates were negative for rhlI and rhlR and three isolates were negative for all four genes. The isolates that were negative for virulence factor production were generally less susceptible to the antimicrobials and statistically significant correlations were observed between the lack of elastase production and resistance to piperacillin and ceftazidime; between failure in alkaline protease production and resistance to tobramycin, piperacillin, piperacillin-tazobactam, cefepime, imipenem and ciprofloxacin; and between failure in pyocyanin production and resistance to amikacin, tobramycin, ceftazidime, ciprofloxacin and ofloxacin. The results obtained indicate that, despite the pivotal role of QS in the pathogenesis of P. aeruginosa respiratory infections, QS-deficient strains are still capable of causing infections and tend to be less susceptible to antimicrobials.