Prevalence and molecular epidemiology of Staphylococcus aureus nasal colonization in four nursing home residents in Crete, Greece.

Nursing homes are considered as reservoirs for methicillin-resistant Staphylococcus aureus (MRSA). The present study investigated the point prevalence and molecular epidemiology of S. aureus colonization among nursing home residents. The study population comprised of 227 residents, living in four nursing homes of the Heraklion, Crete, Greece area, between January and December 2015. From each nursing home, swabs from the anterior nares of all eligible participants were obtained within a 2-week period. The isolated S. aureus strains were identified and screened by standard microbiological and molecular epidemiological methods. S. aureus carriage was found in 62 out of 227 participants (38.4%) with 33 out of 62 (53.2%) being MRSA. The median age was 83 years (range 52-103). Females were more frequently colonized [47 (75.8%)]. All 33 methicillin resistant Staphylococcus aureus (MRSA) isolates were mecA-positive carrying SCCmec type IV, 30 (91%) the fnbA, and 17 (51.5%) the PVL genes. Thirty-two (97%) belonged to a single pulsotype C; among them, the PVL-positives belonged to ST80 clone, whereas, the PVL-negatives to ST225. Among the 33 MRSA isolates, 32 (97%) were clindamycin-resistant, carrying the ermA gene. Methicillin-susceptible Staphylococcus aureus (MSSA) strains showed polyclonality and 76% were PVL-positive. In conclusion the present study has shown that nursing homes in our area can be regarded as important reservoirs for community-associated MRSA (CA-MRSA).

Clostridium difficile in Crete, Greece: epidemiology, microbiology and clinical disease.

We studied the epidemiology and microbiology of Clostridium difficile and the characteristics of patients with C. difficile infection (CDI) in Crete in three groups of hospitalized patients with diarrhoea: group 1 [positive culture and positive toxin by enzyme immunoassay (EIA)]; group 2 (positive culture, negative toxin); group 3 (negative culture, negative toxin). Patients in group 1 were designated as those with definitive CDI (20 patients for whom data was available) and matched with cases in group 2 (40 patients) and group 3 (40 patients). C. difficile grew from 6% (263/4379) of stool specimens; 14·4% of these had positive EIA, of which 3% were resistant to metronidazole. Three isolates had decreased vancomycin susceptibility. Patients in groups 1 and 2 received more antibiotics (P = 0·03) and had more infectious episodes (P = 0·03) than patients in group 3 prior to diarrhoea. Antibiotic administration for C. difficile did not differ between groups 1 and 2. Mortality was similar in all three groups (10%, 12·5% and 5%, P = 0·49). CDI frequency was low in the University Hospital of Crete and isolates were susceptible to metronidazole and vancomycin.

Characteristics, risk factors and outcomes of adult cancer patients with extensively drug-resistant Pseudomonas aeruginosa infections.

OBJECTIVE: To evaluate the characteristics and outcomes of cancer patients with extensively drug-resistant (XDR) Pseudomonas aeruginosa infections. METHODS: This was a retrospective cohort of P. aeruginosa infections in cancer patients in Crete, Greece. Patients were followed until discharge. Mortality, predictors of mortality and risk factors for XDR P. aeruginosa infection were studied. RESULTS: Ninety seven episodes (89 patients) of P. aeruginosa infections (52 with bacteremia) were included in the study. In 22 cases, the infection was due to XDR isolates. All XDR isolates were susceptible to colistin and variably resistant to almost all other antibiotics. The multivariate analysis showed that the independent risk factors for XDR P. aeruginosa infection were hematologic malignancy (OR 40.7, 95 % CI 4.5-367.6) and prior fluoroquinolone use (OR 11.0, 95 % CI 2.0-60.5); lymphopenia was inversely associated with XDR infections (OR 0.16, 95 % CI 0.03-0.92). Mortality was 43 %; infection-related mortality was 24 %. Bacteremia (OR 8.47, 95 % CI 2.38-30.15), infection due to XDR isolates (OR 5.11, 95 % CI 1.15-22.62) and age (OR 1.05, 95 % CI 1.00-1.09) were independently associated with mortality. CONCLUSION: Mortality in cancer patients with P. aeruginosa infections was high. Infection due to XDR isolates was independently associated with mortality.

Trends of isolation of intrinsically resistant to colistin Enterobacteriaceae and association with colistin use in a tertiary hospital.

The objective of this investigation was to evaluate the association between colistin consumption and the isolation of intrinsically resistant to colistin Enterobacteriaceae (IRCE) in a university hospital in Crete, Greece. The database of the microbiological laboratory was reviewed retrospectively during 2006-2010. All positive cultures for IRCE were retrieved. We assessed the total consumption of colistin in medical, surgical, and intensive care units (ICUs). A total of 1,304 single-patient IRCE isolates were recorded. Of these, 466 (35.7%) were hospital-acquired, while 838 (64.3%) were community-acquired. Proteus spp. accounted for 72% of them, Serratia spp. for 16.6%, Morganella morganii for 8.4%, and Providencia spp. for 3%. Urine (44.8%), pus (20.4%), and lower respiratory tract specimens (12.8%) accounted for the majority of specimens. IRCE isolated during the first half (2006 to 1st semester of 2008) and second half (2nd semester of 2008 to 2010) of the study period accounted for 5.8% and 7.4% of Gram-negative isolates, respectively (p < 0.001). Colistin consumption was not different in the two periods in the hospital, but in the ICU, it was higher in the second half of the study period (p = 0.013). Colistin consumption was associated with the isolation of hospital-acquired IRCE (p = 0.037); a trend was noted between colistin consumption and the isolation of IRCE in the ICU (p = 0.057). In this study, colistin consumption was associated with the isolation of hospital-acquired IRCE. The use of colistin increased in the ICU during the study period. Prudent use of colistin is essential for the prevention of nosocomial outbreaks due to resistant IRCE.

Staphylococcus aureus nasal carriage might be associated with vitamin D receptor polymorphisms in type 2 diabetes.

Vitamin D receptor (VDR) gene polymorphisms have been associated with susceptibility to several diseases, including type 1 diabetes (T1D), type 2 diabetes (T2D), and various infections. The study investigated whether VDR gene polymorphisms influence nasal carriage of Staphylococcus aureus in individuals with T2D, an important source for bloodstream, surgical site and other nosocomial infections. In 173 patients with T2D genotyped for the VDR gene polymorphisms on FokI (rs10735810) F>f, BsmI (rs1544410) B>b, ApaI (rs7975232) A>a, and TaqI (rs731236) T>t, a nasal swab was obtained to detect colonization by S. aureus. A repeat swab was obtained in 162/173 subjects for the estimation of persistent S. aureus carriage. The prevalence of S. aureus nasal colonization was 19.7% and of persistent carriage was 8.6%. Nasal colonization by S. aureus was more common in individuals with FokI f allele than F allele (p 0.05; OR 1.69, 95% CI 1.00-2.89) and individuals with FokI ff genotypes were more frequently colonized than those with FokI FF and Ff genotypes combined (p 0.03; OR 2.61, 95% CI 1.14-5.99). The presence of the FokI f allele was related to higher rates of S. aureus persistent nasal colonization (p 0.002; OR 3.53, 95% CI 1.56-7.98), and individuals with a FokI ff genotype were more often persistent carriers than those with FokI FF and Ff genotypes combined (p <0.001; OR 7.32, 95% CI 2.39-22.41). This study is the first, to our knowledge, to show an association between FokI polymorphism in the VDR gene and nasal carriage of S. aureus in individuals with T2D.

Antimicrobial activity of prulifloxacin in comparison with other fluoroquinolones against community-acquired urinary and respiratory pathogens isolated in Greece.

Prulifloxacin, the prodrug of ulifloxacin, is a broad-spectrum fluoroquinolone rather recently introduced in certain European countries. We compared the antimicrobial potency of ulifloxacin with that of other fluoroquinolones against common urinary and respiratory bacterial pathogens. The microbial isolates were prospectively collected between January 2007 and May 2008 from patients with community-acquired infections in Greece. Minimum inhibitory concentrations (MICs) were determined for ciprofloxacin, levofloxacin, moxifloxacin (for respiratory isolates only), and ulifloxacin using the E-test method. The binary logarithms of the MICs [log2(MICs)] were compared by using the Wilcoxon signed-ranks test. A total of 409 isolates were studied. Ulifloxacin had the lowest geometric mean MIC for the 161 Escherichia coli, 59 Proteus mirabilis, and 22 Staphylococcus saprophyticus urinary isolates, the second lowest geometric mean MIC for the 38 Streptococcus pyogenes respiratory isolates (after moxifloxacin), and the third lowest geometric mean MIC for the 114 Haemophilus influenzae and the 15 Moraxella catarrhalis respiratory isolates (after ciprofloxacin and moxifloxacin). Compared with levofloxacin, ulifloxacin had lower log2(MICs) against E. coli (p < 0.001), P. mirabilis (p < 0.001), S. saprophyticus (p < 0.001), and S. pyogenes (p < 0.001). Compared with ciprofloxacin, ulifloxacin had lower log2(MICs) against P. mirabilis (p < 0.001), S. saprophyticus (p = 0.008), and S. pyogenes (p < 0.001), but higher log2(MICs) against H. influenzae (p < 0.001) and M. catarrhalis (p = 0.001). In comparison with other clinically relevant fluoroquinolones, ulifloxacin had the most potent antimicrobial activity against the community-acquired urinary isolates studied and very good activity against the respiratory isolates.

Antimicrobial susceptibility of non-fermenting Gram-negative isolates to isepamicin in a region with high antibiotic resistance.

The alarmingly increasing resistance rates among non-fermenting Gram-negative species, particularly Pseudomonas aeruginosa and Acinetobacter baumannii, intensified the interest in alternative antibiotic treatment options. Isepamicin, an old aminoglycoside, may play a role in the treatment of patients with infections caused by those multi-drug resistant pathogens. We evaluated the antimicrobial activity of isepamicin against non-fermenting Gram-negative isolates collected of the microbiological laboratory at the University Hospital of Heraklion, Crete, Greece from 2004 to the first trimester of 2011. We tested a total of 4,219 isolates (66.2 % Pseudomonas spp., 30 % Acinetobacter spp., 3.8 % other non-fermenters). The lower respiratory tract, pus, and urine were the most frequent sites of isolation (29.7 %, 19.9 %, and 12.9 %, respectively). Overall, 2768 (65.6 %) of the evaluated isolates were susceptible to isepamicin (including 79.9 % of Pseudomonas spp, 37.2 % of Acinetobacter spp, 43.1 % of other non-fermenters). Isepamicin exhibited higher antimicrobial activity compared to broad spectrum penicillins, cephalosporins, other aminoglycosides, carbapenems, and fluoroquinolones. Only colistin was more active than isepamicin. Additionally, 41.7 % of carbapenem-resistant and 53.2 % of colistin-resistant P. aeruginosa isolates were susceptible to isepamicin. The susceptibility rates for the respective types of A. baumannii isolates were 12 % and 6.2 %. Yet, isepamicin was active against 29.2 % of A. baumannii that were resistant to all other tested aminoglycosides. Isepamicin exhibits considerable antimicrobial activity against Gram-negative non-fermenters in a region with high antimicrobial resistance. Particularly, isepamicin may provide a therapeutic option for infections from carbapenem- and colistin-resistant P. aeruginosa and other aminoglycoside-resistant A. baumannii. Further modifications in the aminoglycoside molecule may provide formulations with enhanced antimicrobial activity.

Epidemiology of dermatophytoses in Crete, Greece between 2004 and 2010.

AIM: The present work was undertaken in order to study the epidemiology of dermatophytoses in the island of Crete, Greece, over a 7-year period (2004-2010) and to compare the results with those reported earlier from this region and from other parts of the world. METHODS: A total of 3236 clinical specimens obtained from 2674 patients with signs of dermatomycoses were examined by direct micropscopy and culture. RESULTS: Overall, 392 specimens (12.1%) were proved mycologically positive for dermatophytes. The age of the patients ranged from 2 to 90 years (mean age, 41 years). Onychomycosis was the predominant clinical type of infection, followed by tinea pedis, tinea corporis, tinea capitis, tinea faciei, tinea manuum and tinea cruris. Among dermatophytes, nine species were isolated: Trichophyton rubrum (51%), Microsporum canis (18.9%), Trichophyton mentagrophytes var. interdigitale (18.4%), Trichophyton mentagrophytes var. mentagrophytes (5.1%), Epidermophyton floccosum (3.6%), Microsporum gypseum (1.5%), Trichophyton violaceum (0.8%), Trichophyton verrucosum (0.5%) and Trichophyton tonsurans (0.2%). CONCLUSION: In our area, the most common dermatophyte was T. rubrum followed by M. canis. Epidemiological studies regarding the current prevalence of dermatophytes in a certain region are needed for the appropriate management of these infections and implementation of effective prevention and control measures.

Pseudomonas aeruginosa urinary tract infection in children: risk factors and outcomes.

PURPOSE: Pseudomonas aeruginosa is an unusual uropathogen that is mostly responsible for nosocomial or catheter associated urinary tract infections in adults. Data about P. aeruginosa urinary tract infections in children are scarce. We investigated P. aeruginosa urinary tract infections in children in a well-defined area. MATERIALS AND METHODS: Clinical, laboratory and radiological characteristics of all children with P. aeruginosa urinary tract infections were compared to those of gender matched children with community acquired Escherichia coli urinary tract infections during a 12-year period. RESULTS: A total of 35 children with 43 P. aeruginosa urinary tract infection episodes representing 6.7% of total urinary tract infection cases during the study period were compared to 70 children with E. coli urinary tract infections. Children with P. aeruginosa more often presented with a history of at least 1 previous urinary tract infection episode (p <0.0001), hospitalization (p = 0.0001), use of antibiotics (p = 0.0001), malformations predisposing to urinary tract infections (p = 0.004), vesicoureteral reflux (p <0.0001), abnormal dimercapto-succinic acid scan (p = 0.0003), longer hospitalization and surgery. Use of antibiotics either as prophylaxis or as treatment within the preceding 2 months was demonstrated by multivariate logistic regression analysis as the single independent risk factor for P. aeruginosa urinary tract infections (odds ratio 21.6, 95% CI 4.65-100, p = 0.0001). P. aeruginosa isolates were often resistant to gentamicin (27.9%) and ceftazidime (13.9%) but remained sensitive to carbapenems and ciprofloxacin. CONCLUSIONS: P. aeruginosa urinary tract infection is associated with distinct risk factors and outcomes, and should be considered in predisposed children with symptoms of urinary tract infection who are on prophylaxis or have a history of a recent course of antibiotics.

Synergy of fosfomycin with carbapenems, colistin, netilmicin, and tigecycline against multidrug-resistant Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa clinical isolates.

Fosfomycin represents a potential last-resort treatment option for infections with certain multidrug-resistant (MDR) Gram-negative pathogens. We evaluated double-drug combinations of fosfomycin with imipenem, meropenem, doripenem, colistin, netilmicin, and tigecycline for in vitro synergy against 100 MDR Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa clinical isolates, using the Etest method. Synergy was defined as a fractional inhibitory concentration index ≤ 0.5. The isolates were consecutively collected at a university hospital in Greece from various clinical specimens. Against 50 serine carbapenemase-producing K. pneumoniae isolates, synergy of fosfomycin with imipenem, meropenem, doripenem, colistin, netilmicin, and tigecycline was observed for 74.0%, 70.0%, 74.0%, 36.0%, 42.0%, and 30.0% of the isolates, respectively. Against 14 extended-spectrum ß-lactamase (ESBL)-producing K. pneumoniae isolates, synergy of fosfomycin with imipenem, meropenem, doripenem, colistin, netilmicin, and tigecycline was observed for 78.6%, 42.9%, 42.9%, 7.1%, 42.9%, and 21.4%, respectively; for 20 ESBL-producing E. coli isolates, the corresponding values were 55.0%, 25.0%, 30.0%, 15.0%, 25.0%, and 25.0%; and for 15 MDR P. aeruginosa isolates, the corresponding values were 46.7%, 53.3%, 73.3%, 13.3% , 13.3%, and 13.3%. Antagonism was not observed for any of the combinations tested. Further studies are needed in order to confirm the clinical relevance of the above findings.

Long-term trends in the epidemiology and resistance of childhood bacterial enteropathogens in Crete.

In this study, we investigated the long-term trends in the epidemiology and susceptibility of bacterial enteropathogens among children in a well-defined area of adequate health standards. The study included all children younger than 14 years of age treated for enteritis at Heraklion University General Hospital on the island of Crete during the 18-year period from January 1993 to December 2010. Stool specimens were tested for Salmonella, Shigella, Campylobacter, enteropathogenic Escherichia coli (EPEC), Yersinia, and Aeromonas species. Of the 33,032 stool samples from patients of any age, 2,912 (8.82%) were positive for bacterial enteropathogens. The 1,597 isolates from children were identified as S. enterica (42.3%), Campylobacter spp. (33.6%), EPEC (17.4%), Y. enterocolitica (5.82%), A. hydrophila (0.44%), and Shigella spp. (0.38%). A decline in prevalence was observed for all bacterial enteropathogens. Taken as a total, enteropathogens were susceptible to gentamicin, ceftriaxone, ciprofloxacin, co-trimoxazole, and amoxicillin in 98.8%, 88.0%, 83.0%, 67.1%, and 59.6%, respectively. During the study period, the susceptibility rates decreased for co-trimoxazole (p<0.0001) and ciprofloxacin (p<0.001), and increased for amoxicillin (p<0.0001). Our findings suggest declining long-term trends in the prevalence of bacterial enteropathogens and changes in susceptibility rates to first-line antibacterial agents. These changing trends in the long-term morbidity and susceptibility call for ongoing surveillance and tailored management.

Infant colonization by Staphylococcus aureus: role of maternal carriage.

Infant colonization by Staphylococcus aureus has not been adequately investigated. In this study, we aimed to define determinants associated with the carriage of S. aureus in early infancy. Serial nasal swabs were collected from 128 infants and their mothers at months 0, 6, and 12 postpartum. S. aureus isolates were characterized by pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), spa typing, and the presence of chromosomal mecA and of Panton-Valentine leukocidin (PVL) genes. S. aureus was isolated in 17.7% and 15.7% of swabs from infants and mothers, respectively. Carriage rates were higher in infants with carrier mothers, non-smoking mothers, and many siblings. Persistent carriage rates were higher in infants with carrier or non-smoking mothers. S. aureus typing revealed identical strains in 10/15 investigated infant-mother pairs. Among 19 investigated S. aureus isolates from infants, ten harbored mecA and two harbored PVL genes, and these determinants were concomitantly present in isolates from mothers. Resistance to methicillin was 43.6% among all isolates from infants. In conclusion, isolates from infants were commonly identical to isolates from their mothers, pointing to a principal role of maternal carriage in S. aureus colonization in infants.

Serratia infections in a general hospital: characteristics and outcomes.

We aimed to present our experience regarding infections caused by Serratia spp. in a region with relatively high antimicrobial resistance rates. We retrospectively reviewed the databases of the microbiological laboratory of the University Hospital of Heraklion, Crete (2/2004-12/2009). A total of 77 patients [67.5% men, mean age ± standard deviation (SD) = 56.9 ± 24.5 years) were identified; 37.7% were outpatients. Sixty-five (84.4%) of the 77 included patients had a Serratia marcescens isolate; the remaining 12 patients had a non-marcescens Serratia spp. The most frequently observed infections were respiratory tract infection (32.5%) and keratitis/endophthalmitis (20.8%). Seventy-three (94.9%) patients were cured. Four deaths were observed; three of them were considered as attributed to the Serratia infection. No difference was found regarding the characteristics and outcomes between patients with Serratia marcescens and non-marcescens infections. In addition, antipseudomonal penicillins and their combinations with beta-lactamase inhibitors, as well as carbapenemes, and fluoroquinolones exhibited high antimicrobial activity against both the tested Serratia marcescens and non-marcescens isolates. Our study adds useful information regarding the characteristics and outcomes of patients with Serratia infection, as well as the susceptibilities of the respective Serratia marcescens and non-marcescens isolates, in a region with relatively high levels of antimicrobial resistance.

Saccharomyces boulardii and Candida albicans experimental colonization of the murine gut.

Saccharomyces boulardii has been and continues to be extensively used as a probiotic, with only rare associations with fungemia. This study evaluated the virulence of this yeast when given as a probiotic, and its role in preventing gastrointestinal (GI) colonization by Candida. Adult male Crl:CD1 (ICR) BR mice were given S. boulardii orally in three different doses or normal saline for 14 days. Stool cultures were performed at the time of discontinuation of yeast administration, as well as 1 and 2 weeks later. Gut colonization was proportional to the given dose but lasted only 1 week and no dissemination of the yeast was detected. S. boulardii was also given for 2 and 4 weeks to mice fed chow containing Candida albicans. S. boulardii in the gut did not affect Candida GI colonization. These findings suggest that oral administration of S. boulardii induces a substantial but short term increase of this yeast in the intestinal lumen and administration of the probiotic does not prevent subsequent GI colonization by C. albicans.

Effects of levofloxacin, moxifloxacin and prulifloxacin on murine gut colonization by Candida albicans.

Fluoroquinolones are broad-spectrum antibiotics increasingly utilized as empirical or prophylactic therapy in the management of cancer patients. We evaluated the effects of newer generation fluoroquinolones on the level of gastrointestinal (GI) colonization by Candida albicans in a previously established mouse model. Adult male Crl:CD1 (ICR) BR mice were fed chow containing Candida albicans or regular chow. The mice fed the Candida chow had their gut colonized by the yeast. Both groups were subsequently given levofloxacin, moxifloxacin, prulifloxacin or normal saline for 10 days. Stool cultures were performed immediately before, at the end, and one week after discontinuation of treatment to determine the level of intestinal yeast colonization. Candida-colonized mice treated with fluoroquinolones had substantially higher yeast counts in their stools than control mice fed Candida containing chow but treated with saline. Mice fed regular chow and treated with the study antibiotics or saline did not have any Candida in their stools. Dissemination of Candida to internal organs was not observed in any animal. In conclusion, we have shown that all fluoroquinolones tested induced substantial increases in the murine intestinal concentration of C. albicans.

Resistance status and evolution trends of Klebsiella pneumoniae isolates in a university hospital in Greece: ineffectiveness of carbapenems and increasing resistance to colistin.

BACKGROUND: Due to its increased non-susceptibility rates, Klebsiella pneumoniae has emerged as one of the most problematic pathogens. METHODS: The level of resistance to 25 antimicrobials of K. pneumoniae isolates from a teaching hospital in Greece and the evolution trends during 2 decades were examined. RESULTS: A statistically significant increase in non-susceptibility rates was found for almost all antimicrobials examined. During 2008, the isolates presented non-susceptibility rates to aminoglycosides >50% and to quinolones >60%. Nowadays, 1 out of 10 isolates is non-susceptible to colistin. Moreover, the isolates non-susceptible to imipenem were almost doubled between 2007 (29%) and 2008 (50%). Among the imipenem-resistant isolates, 1 out of 4 was also resistant to colistin. CONCLUSION: The effectiveness of carbapenems has been compromised and the increase in resistance to colistin is rapid and steep.