In Vitro Activity of Dalbavancin and Fourteen Other Antimicrobial Agents Against Toxigenic Clostridioides Difficile Clinical Isolates in a Greek Tertiary-Care Hospital.

OBJECTIVE: Clostridioides difficile is a major cause of healthcare-associated diarrhea worldwide. For years, metronidazole and vancomycin were considered the standard treatment for C. difficile infection (CDI). However, they are increasingly being associated with treatment failure and recurrence. In this study we investigated the in vitro activity of dalbavancin and fourteen other antimicrobials against 155 toxigenic C. difficile isolates originating from patients with C. difficile-associated diarrhea. MATERIALS AND METHODS: Antimicrobial susceptibility was evaluated by the MIC Test Strip and the results were interpreted using both the Clinical and Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial susceptibility Testing (EUCAST) breakpoints. RESULTS: C. difficile isolates were fully susceptible to metronidazole, vancomycin, amoxicillin/ clavulanate, piperacillin/tazobactam, and tigecycline. All isolates were dalbavancin susceptible by the CLSI breakpoint (≤ 0.25 µg/ml) compared with 97.4% susceptibility by the EUCAST breakpoint (≤ 0.125 µg/ml). Dalbavancin demonstrated significantly lower MIC50 and MIC90 values compared to vancomycin (0.047 vs. 0.38 and 0.125 vs. 0.5, respectively, p < 0.001). Resistance rates to penicillin, ampicilin, cefoxitin, imipenem, meropenem, clindamycin, moxifloxacin, chloramphenicol, and tetracycline were 20%, 14.2% , 100%, 75.5%, 0.6%, 51%, 36.1%, 3.2%, and 14.8%, respectively. Multidrug-resistant (MDR) phenotypes were detected among 41.3% of the isolates. CONCLUSION: Dalbavancin exhibited potent activity against the isolates tested. As C. difficile is an important healthcare-associated pathogen, continued surveillance is required to monitor for development of resistance.

Prevalence and antimicrobial resistance of bacterial enteropathogens in Crete, Greece, during 2011-2022.

Diarrheal diseases are of great concern worldwide and are responsible for considerable morbidity and mortality. This study investigated the epidemiology and the antibiotic susceptibility of bacterial enteropathogens among diarrheal patients of all ages in Crete, Greece during 2011-2022. Stool specimens were tested by conventional cultural methods for Salmonella, Shigella, Campylobacter, diarrheagenic Escherichia coli (EPEC, STEC), Yersinia enterocolitica, Aeromonas species and Clostridioides difficile. Antimicrobial susceptibility was determined by the disk diffusion method for Enterobacterales, Campylobacter and Aeromonas, and by the gradient diffusion method for C. difficile. Of the 26,060 stool samples from patients of any age, 1,022 (3.9%) were positive for bacterial enteropathogens. Campylobacter spp. were the most commonly isolated bacteria (56.4%), followed by Salmonella enterica (32.3%), and E. coli (EPEC, STEC) (6.5%). Toxigenic C. difficile was isolated from 341 out of 8,848 diarrheal specimens examined (3.9%). Resistance to ampicillin was observed in 12.4% of Salmonella, 66.7% of Shigella and 34.8% of E. coli (EPEC, STEC) isolates. Resistance to trimethoprim/sulfamethoxazole was observed in 5.8% of Salmonella, 33.3% of Shigella, and 15.1% of E. coli (EPEC, STEC) isolates. High rates of ciprofloxacin resistance (77.3%) were detected among Campylobacter isolates, while resistance to erythromycin was observed in 2.4% of them. All C. difficile isolates were susceptible to vancomycin and metronidazole. Our findings suggest declining trends in prevalence of bacterial enteropathogens, except for Campylobacter spp. and changes in the susceptibility rates to antimicrobials. Continuous surveillance of prevalence and antimicrobial susceptibility of bacterial enteropathogens is mandatory for implementing targeted and effective prevention and infection control measures.

Antimicrobial Resistance of Streptococcus pneumoniae Clinical Serotypes between 2017 and 2022 in Crete, Greece.

BACKGROUND: Pneumococcal disease is still considered a global problem. With the introduction of pneumococcal conjugate vaccines (PCVs) serotype epidemiology changed, but antimicrobial resistance persists constituting a serious problem. The current study aimed to determine the serotype distribution and the antimicrobial susceptibility of recent Streptococcus pneumoniae isolates, following implementation of the 13-valent conjugate vaccine (PCV13). MATERIALS AND METHODS: From January 2017 to December 2022 we evaluated 116 nonduplicate S. pneumoniae isolates collected from adult patients (21 - 98 years) cared for in the University Hospital of Heraklion, Crete, Greece. Pneumococcal isolates were serotyped by the Quellung reaction, and antimicrobial susceptibility testing was performed using E-test. Multidrug resistance (MDR) was defined as non-susceptibility to at least one agent in ≥3 classes of antibiotics. RESULTS: Among the 116 isolates, 31% were recognized as invasive pneumococcal strains, while 69% were non-invasive. The isolates tested belonged to 25 different serotypes. The most prevalent serotypes were 11A (10.3%), and 35B (10.3%), followed by 3 (9.5%), 15A (7.8%), 25F (6.9%), 19A (5.3%), 35F (5.3%), and others (44.6%). The coverage rates of PCV13 and the pneumococcal polysaccharide vaccine (PPSV23) were 26.7% and 57.8%, respectively. PCV13 and PPSV23 serotypes decreased between 2017 - 2019 and 2020 - 2022, with a parallel increase in the non-vaccine types. Resistance rates to erythromycin, clindamycin, trimethoprim/sulfamethoxazole, penicillin, levofloxacin, and ceftriaxone, were 40.5%, 21.6%, 13.8%, 12.1%, 3.4%, and 0%, respectively. All isolates were susceptible to vancomycin, linezolid, and daptomycin. MDR was observed among 36 (31%) S. pneumoniae isolates. CONCLUSION: The increasing levels of resistance in S. pneumoniae in Crete, Greece, highlight the need for continuous surveillance of antimicrobial resistance and development of strategies for its reduction, including antimicrobial stewardship programs, increased pneumococcal vaccination, and development of next generation PCVs with a wider serotype coverage.

Enterobacterales carrying chromosomal AmpC ß-lactamases in Europe (EuESCPM): Epidemiology and antimicrobial resistance burden from a cohort of 27 hospitals, 2020-2022.

INTRODUCTION: The ESCPM group (Enterobacter species including Klebsiella aerogenes - formerly Enterobacter aerogenes, Serratia species, Citrobacter freundii complex, Providencia species and Morganella morganii) has not yet been incorporated into systematic surveillance programs. METHODS: We conducted a multicentre retrospective observational study analysing all ESCPM strains isolated from blood cultures in 27 European hospitals over a 3-year period (2020-2022). Diagnostic approach, epidemiology, and antimicrobial susceptibility were investigated. RESULTS: Our study comprised 6,774 ESCPM isolates. MALDI-TOF coupled to mass spectrometry was the predominant technique for bacterial identification. Susceptibility to new ß-lactam/ß-lactamase inhibitor combinations and confirmation of AmpC overproduction were routinely tested in 33.3% and 29.6% of the centres, respectively. The most prevalent species were E. cloacae complex (44.8%) and S. marcescens (22.7%). Overall, third-generation cephalosporins (3GC), combined third- and fourth-generation cephalosporins (3GC + 4GC) and carbapenems resistance phenotypes were observed in 15.7%, 4.6%, and 9.5% of the isolates, respectively. AmpC overproduction was the most prevalent resistance mechanism detected (15.8%). Among carbapenemase-producers, carbapenemase type was provided in 44.4% of the isolates, VIM- (22.9%) and OXA-48-enzyme (16%) being the most frequently detected. E. cloacae complex, K. aerogenes and Providencia species exhibited the most notable cumulative antimicrobial resistance profiles, with the former displaying 3GC, combined 3GC + 4GC and carbapenems resistance phenotypes in 15.2%, 7.4%, and 12.8% of the isolates, respectively. K. aerogenes showed the highest rate of both 3GC resistant phenotype (29.8%) and AmpC overproduction (32.1%), while Providencia species those of both carbapenems resistance phenotype (42.7%) and carbapenemase production (29.4%). ESCPM isolates exhibiting both 3GC and combined 3GC + 4GC resistance phenotypes displayed high susceptibility to ceftazidime/avibactam (98.2% and 95.7%, respectively) and colistin (90.3% and 90.7%, respectively). Colistin emerged as the most active drug against ESCPM species (except those intrinsically resistant) displaying both carbapenems resistance phenotype (85.8%) and carbapenemase production (97.8%). CONCLUSIONS: This study presented a current analysis of ESCPM species epidemiology in Europe, providing insights to inform current antibiotic treatments and guide strategies for antimicrobial stewardship and diagnostics.

Clinical and microbiological characteristics of nocardiosis: A 5-year single-center study in Crete, Greece.

Nocardiosis is a rare disease affecting both immunocompromised and immunocompetent hosts, presented in various clinical forms ranging from localized to disseminated infection. Aim of the present study was to investigate the clinical and microbiological characteristics of nocardiosis, antimicrobial resistance profiles, treatment, and outcomes of Nocardia infection over the last 5 years at our institution. The medical records and microbiological data of patients affected by nocardiosis and treated at the university hospital of Heraklion, Crete, Greece, between 2018 and 2022, were retrospectively analyzed. The isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and through sequencing of 16S rRNA. Antimicrobial susceptibility for 17 agents was determined by E-test and results were interpreted according to CLSI guidelines. Among the 28 Nocardia isolates, eight species were identified, with Nocardia brasiliensis being the most prevalent (32.1%), followed by Nocardia otitidiscaviarum (25%), and Nocardia farcinica (14.3%). Skin and soft tissue infections were the most common presentations, noted in 13 (50%) patients, followed by pulmonary infection presented in 10 (38.5%) patients. Fifteen patients (57.7%) had at least one underlying disease, and 11 (42.3%) were on immunosuppressive or long-term corticosteroid treatment. Susceptibility rates of linezolid, tigecycline, amikacin, trimethoprim-sulfamethoxazole, moxifloxacin, and imipenem were 100, 100, 96.4, 92.9, 82.1, and 42.9%, respectively. The 26 patients in this study were treated with various antibiotics. Mortality rate was 3.8%, and the patient who died had disseminated infection. Since epidemiology and antimicrobial susceptibility are evolving, continuous surveillance is mandatory in order to initiate appropriate treatment in a timely manner.

In vitro activities of omadacycline, eravacycline, cefiderocol, apramycin, and comparator antibiotics against Acinetobacter baumannii causing bloodstream infections in Greece, 2020-2021: a multicenter study.

Resistance of Acinetobacter baumannii to multiple clinically important antimicrobials has increased to very high rates in Greece, rendering most of them obsolete. The aim of this study was to determine the molecular epidemiology and susceptibilities of A. baumannii isolates collected from different hospitals across Greece. Single-patient A. baumannii strains isolated from blood cultures (n = 271), from 19 hospitals, in a 6-month period (November 2020-April 2021) were subjected to minimum inhibitory concentration determination and molecular testing for carbapenemase, 16S rRNA methyltransferase and mcr gene detection and epidemiological evaluation. 98.9% of all isolates produced carbapenemase OXA-23. The vast majority (91.8%) of OXA-23 producers harbored the armA and were assigned mainly (94.3%) to sequence group G1, corresponding to IC II. Apramycin (EBL-1003) was the most active agent inhibiting 100% of the isolates at ≤16 mg/L, followed by cefiderocol which was active against at least 86% of them. Minocycline, colistin and ampicillin-sulbactam exhibited only sparse activity (S <19%), while eravacycline was 8- and 2-fold more active than minocycline and tigecycline respectively, by comparison of their MIC50/90 values. OXA-23-ArmA producing A. baumannii of international clone II appears to be the prevailing epidemiological type of this organism in Greece. Cefiderocol could provide a useful alternative for difficult to treat Gram-negative infections, while apramycin (EBL-1003), the structurally unique aminoglycoside currently in clinical development, may represent a highly promising agent against multi-drug resistant A. baumanni infections, due to its high susceptibility rates and low toxicity.

In Vitro Activities of Ceftobiprole, Dalbavancin, Tedizolid and Comparators against Clinical Isolates of Methicillin-Resistant Staphylococcus aureus Associated with Skin and Soft Tissue Infections.

Skin and soft tissue infections (SSTIs) are associated with significant morbidity and healthcare costs, especially when caused by methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin is a preferred antimicrobial therapy for the management of complicated SSTIs (cSSTIs) caused by MRSA, with linezolid and daptomycin regarded as alternative therapeutic options. Due to the increased rates of antimicrobial resistance in MRSA, several new antibiotics with activity against MRSA have been recently introduced in clinical practice, including ceftobiprole, dalbavancin, and tedizolid. We evaluated the in vitro activities of the aforementioned antibiotics against 124 clinical isolates of MRSA obtained from consecutive patients with SSTIs during the study period (2020-2022). Minimum inhibitory concentrations (MICs) for vancomycin, daptomycin, ceftobiprole, dalbavancin, linezolid and tedizolid were evaluated by the MIC Test Strip using Liofilchem strips. We found that when compared to the in vitro activity of vancomycin (MIC90 = 2 µg/mL), dalbavancin possessed the lowest MIC90 (MIC90 = 0.094 µg/mL), followed by tedizolid (MIC90 = 0.38 µg/mL), linezolid, ceftobiprole, and daptomycin (MIC90 = 1 µg/mL). Dalbavancin demonstrated significantly lower MIC50 and MIC90 values compared to vancomycin (0.064 vs. 1 and 0.094 vs. 2, respectively). Tedizolid exhibited an almost threefold greater level of in vitro activity than linezolid, and also had superior in vitro activity compared to ceftobiprole, daptomycin and vancomycin. Multidrug-resistant (MDR) phenotypes were detected among 71.8% of the isolates. In conclusion, ceftobiprole, dalbavancin and tedizolid exhibited potent activity against MRSA and are promising antimicrobials in the management of SSTIs caused by MRSA.

Examining the Prevalence and Antibiotic Susceptibility of S. aureus Strains in Hospitals: An Analysis of the pvl Gene and Its Co-Occurrence with Other Virulence Factors.

S. aureus is a pathogenic bacterium that causesinfections. Its virulence is due to surface components, proteins, virulence genes, SCCmec, pvl, agr, and SEs, which are low molecular weight superantigens. SEs are usually encoded by mobile genetic elements, and horizontal gene transfer accounts for their widespread presence in S. aureus. This study analyzed the prevalence of MRSA and MSSA strains of S. aureus in two hospitals in Greece between 2020-2022 and their susceptibility to antibiotics. Specimens collected were tested using the VITEK 2 system and the PCR technique to detect SCCmec types, agr types, pvl genes, and sem and seg genes. Antibiotics from various classes were also tested. This study examined the prevalence and resistance of S. aureus strains in hospitals. It found a high prevalence of MRSA and that the MRSA strains were more resistant to antibiotics. The study also identified the genotypes of the S. aureus isolates and the associated antibiotic resistances. This highlights the need for continued surveillance and effective strategies to combat the spread of MRSA in hospitals. This study examined the prevalence of the pvl gene and its co-occurrence with other genes in S. aureus strains, as well as their antibiotic susceptibility. The results showed that 19.15% of the isolates were pvl-positive and 80.85% were pvl-negative. The pvl gene co-existed with other genes, such as the agr and enterotoxin genes. The results could inform treatment strategies for S. aureus infections.

In vitro activity of newer ß-lactam/ß-lactamase inhibitor combinations, cefiderocol, plazomicin and comparators against carbapenemase-producing Klebsiella pneumoniae isolates.

Infections by carbapenem-resistant Klebsiella pneumoniae (CRKP) remain one of the greatest healthcare threats associated with significant morbidity and mortality. New antimicrobials were recently developed to address this threat. We assessed the epidemiology of carbapenemase-producing K. pneumoniae (CPKP) isolates recovered in a Greek university hospital during 2021, and their susceptibilities to old and newer antimicrobials. Minimum inhibitory concentrations (MICs) were determined by the MIC Test Strip method, except for cefiderocol (CFDC) and colistin that were evaluated by the broth microdilution method. A total of 110 CPKP strains were isolated, with KPC-producers being the most prevalent (64.6%). Among the agents tested, plazomicin (PL) displayed the highest activity against all the isolates (MIC50/MIC90, 0.5/1.5 µg/ml), followed by tigecycline (MIC50/MIC90, 1.5/4 µg/ml). All KPC-producing K. pneumoniae were susceptible to ceftazidime-avibactam (CAZ/AVI) and meropenem-vaborbactam (M/V) and 97.2% of them to imipenem-relebactam (I/R). Among the MBL-producing isolates, PL and CFDC exhibited the highest activity.

Nocardia elegans primary iliopsoas abscess: A case report and literature review.

Nocardia species are rare causative agents of psoas abscess, more frequently occurring as part of disseminated infection. Only sporadic cases have been reported so far, with Nocardia asteroides and Nocardia farcinica being the most common causative agents. Nocardia elegans is an opportunistic pathogen, accounting for only 0.3-0.6% of infections caused by Nocardia species, usually affecting the respiratory tract.In this study, a previously healthy 74-year-old man was admitted to the University Hospital of Heraklion with fever and intense pain radiating from the lumbar region to the groin and the left thigh, increasing with movement. Imaging findings revealed a large abscess in the left iliopsoas. Blood and pus aspirate cultures yielded a pure culture of Nocardia that was identified by 16S rRNA sequence as N. elegans. The patient was successfully treated with drainage of the abscess along with administration of ceftriaxone, linezolid and trimethoprim-sulfamethoxazole. To our knowledge, this is the first report of iliopsoas abscess caused by N. elegans. Early, accurate diagnosis and timely treatment with drainage of the abscess and long-term administration of antimicrobial agents optimize the outcome.

A 60-Year Literature Review on Hepatic Actinomycosis.

Hepatic actinomycosis (HA) is a rare infection with an indolent course, atypical clinical manifestations, nonspecific laboratory and imaging findings, and challenging diagnosis. We describe a case of a 35-year-old female who developed HA 2 weeks after gastrectomy. In addition, we analyzed clinical characteristics and outcome of 157 additional cases of HA identified in a 60-year literature review. Patients with HA were predominantly male (57%) and more than one-half were between 40 and 70 years of age. The infection was cryptogenic in 80.8% of cases. Risk factors for HA were identified in 63.1% of the patients. Clinical presentation included fever (57.7%), abdominal pain (52.1%), weight loss (45.1%), anorexia (27.5%), fatigue and chills (12.7% each), and malaise (12%) over a 2.35 ± 3.5 months period. Leukocytosis, elevated alkaline phosphatase, erythrocyte sedimentation rate, and C-reactive protein were the most frequent laboratory findings. Radiologic imaging revealed that the right lobe was more frequently affected (62.5%) with a single lesion found in two-thirds of cases. Diagnosis was achieved by histopathologic examination in 70.6% of cases. Cultures yielded Actinomyces in 45 instances, with A. israelii being the most frequent species. Less than one-half of the patients were treated only with antibiotics, while the others received combined medical and surgical treatment. The median duration of antibiotic therapy was 135 days. The presence of multiple lesions or solid tumor-like lesions (without liquefaction) was significantly associated with medical therapy alone. The outcome was favorable in most cases (94%). Although rarely encountered, HA should be considered in patients with a chronic or subacute inflammatory process of the liver to promptly diagnose and treat.

Epidemiology and in vitro activity of ceftazidime-avibactam, meropenem-vaborbactam, imipenem-relebactam, eravacycline, plazomicin, and comparators against Greek carbapenemase-producing Klebsiella pneumoniae isolates.

BACKGROUND: The increase in carbapenem-resistant Klebsiella pneumoniae (CRKP) infections is of great concern because of limited treatment options. New antimicrobials were recently approved for clinical therapy. This study evaluated the epidemiology of carbapenemase-producing K. pneumoniae isolates collected at a Greek university hospital during 2017-2020, and their susceptibilities to ceftazidime-avibactam (CAZ/AVI), meropenem-vaborbactam (M/V), imipenem-relebactam (I/R), eravacycline, plazomicin, and comparators. METHODS: Minimum inhibitory concentrations (MICs) were evaluated by Etest. Only colistin MICs were determined by the broth microdilution method. Carbapenemase genes were detected by PCR. Selected isolates were typed by multilocus sequence typing (MLST). RESULTS: A total of 266 carbapenemase-producing K. pneumoniae strains were isolated during the 4-year study period. Among them, KPC was the most prevalent (75.6%), followed by NDM (11.7%), VIM (5.6%), and OXA-48 (4.1%). KPC-producing isolates belonged mainly to ST258 and NDM producers belonged to ST11, whereas OXA-48- and VIM producers were polyclonal. Susceptibility to tigecycline, fosfomycin, and colistin was 80.5%, 83.8%, and 65.8%, respectively. Of the novel agents tested, plazomicin was the most active inhibiting 94% of the isolates at ≤ 1.5 µg/ml. CAZ/AVI and M/V inhibited all KPC producers and I/R 98.5% of them. All OXA-48 producers were susceptible to CAZ/AVI and plazomicin. The novel ß-lactam/ß-lactamase inhibitors (BLBLIs) tested were inactive against MBL-positive isolates, while eravacycline inhibited 61.3% and 66.7% of the NDM and VIM producers, respectively. CONCLUSIONS: KPC remains the predominant carbapenemase among K. pneumoniae, followed by NDM. Novel BLBLIs, eravacycline, and plazomicin are promising agents for combating infections by carbapenemase-producing K. pneumoniae. However, the emergence of resistance to these agents highlights the need for continuous surveillance and application of enhanced antimicrobial stewardship.

Ceftazidime-avibactam, meropenen-vaborbactam, and imipenem-relebactam in combination with aztreonam against multidrug-resistant, metallo-ß-lactamase-producing Klebsiella pneumoniae.

The spread of multidrug-resistant (MDR), metallo-ß-lactamase (MBL)-producing Klebsiella pneumoniae represents a major therapeutic challenge. The newly introduced ß-lactam-ß-lactamase inhibitors (BLBLIs), ceftazidime/avibactam (CAZ/AVI), meropenem/vaborbactam (M/V), and imipenem/relebactam (I/R) are inactive against MBLs. The aim of this study was to evaluate the in vitro efficacy of aztreonam (ATM) in combination with CAZ/AVI, M/V, and I/R against 40 MDR, MBL-producing, and serine-ß-lactamases co-producing Klebsiella pneumoniae using the Etest method. Synergy was defined as a fractional inhibitory concentration index ≤0.5. All isolates were resistant to ATM, CAZ/AVI, and I/R and 38/40 (95%) were resistant to M/V. Synergy was observed in 97.5% in the combinations CAZ/AVI-ATM, and I/R-ATM and in 72.5% in the combination M/V-ATM. Further clinical studies are required to confirm the efficacy of these antimicrobial combinations.

Antimicrobial susceptibility patterns of clinically significant Gram-positive anaerobic bacteria in a Greek tertiary-care hospital, 2017-2019.

Antimicrobial resistance among anaerobic bacteria is increasingly recognized with geographic differences. In this study we analyzed the distribution and antimicrobial susceptibility profiles of 358 Gram-positive clinically significant anaerobes, isolated from 2017 to 2019, in a Greek tertiary-care hospital. The species identification was performed by Vitek 2 and conventional biochemical methods, and the antimicrobial susceptibility testing by the E-test method. The antimicrobial agents tested were penicillin, ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam, cefoxitin, imipenem, meropenem, clindamycin, metronidazole, moxifloxacin, chloramphenicol, tigecycline and vancomycin. Clostridioides difficile isolates were also tested against tetracycline. The results were interpreted using the CLSI and the EUCAST breakpoints. Clostridium species accounted for 35.5% of the isolates, followed by Gram-positive cocci (GPAC) (33.2%) and non-spore-forming bacilli (31.3%). Beta-lactams, ß-lactam/ß-lactamase inhibitors, cefoxitin, carbapenems, chloramphenicol, tigecycline and vancomycin proved all effective against the GPAC tested. Clindamycin, moxifloxacin and metronidazole resistance varied among different species of GPAC. Clindamycin and moxifloxacin resistance observed was 10% and 5% for Cutibacterium acnes, 25% and 6.2% for Actinomyces odontolyticus and 40% and 5% for Clostridium perfringens. C. difficile isolates were fully susceptible to metronidazole, vancomycin, and tigecycline. Resistance rates to clindamycin, moxifloxacin and tetracycline were 62.9%, 30% and 24.3%, respectively. These data highlight the need for periodic surveillance to monitor changes in susceptibility profiles.

Surveillance of antimicrobial resistance in recent clinical isolates of Gram-negative anaerobic bacteria in a Greek University Hospital.

The aim of our study was to determine the antimicrobial susceptibility profiles of 267 Gram-negative clinically significant anaerobes, isolated between October 2016 and October 2019, in a Greek university hospital. The species identification was performed by conventional methods and using the Vitek 2 automated system. Antimicrobial susceptibility testing to determine the MICs was performed by the E-test method. The antimicrobial agents tested were penicillin, ampicillin, amoxicillin-clavulanic acid, piperacillin-tazobactam, cefoxitin, imipenem, meropenem, clindamycin, metronidazole, moxifloxacin, chloramphenicol and tigecycline. The results were interpreted using the CLSI and FDA breakpoints. The majority of the isolates belonged to Bacteroides fragilis group (58.8%), followed by Prevotella spp. (23.2%), Fusobacterium spp. (11.2%) and Veillonella spp. (6.4%). The most prevalent types of infection were skin and soft tissue infections (34.8%), and inta-abdomonal infections (29.6%). Among all isolates tested, the lowest rates of resistance (<5%) were detected to carbapenems, metronidazole, chloramphenicol and tigecycline. Resistance to piperacillin-tazobactam was observed in 5.4%, 24.6%, 3.3% and 17.6%, of B. fragilis, B. fragilis group, Fusobacterium spp. and Veillonella spp. isolates, respectively. Although a high prevalence of resistance to clindamycin, cefoxitin, and moxifloxacin, was detected particularly among members of the B. fragilis group, cefoxitin resistance was low for Prevotella spp. (3.2%), Fusobacterium spp. (3.3%) and Veillonella spp. (0%). Our findings underscore the need for periodic monitoring of antimicrobial resistance in order to guide empirical therapy.

Epidemiology and antifungal susceptibility patterns of Candida isolates from Greek women with vulvovaginal candidiasis.

Vulvovaginal candidiasis (VVC) is a common infection of the genital tract affecting millions of women worldwide. Data on epidemiological trends of VVC in Greece are scarce. This study was undertaken to evaluate the prevalence of VVC among symptomatic women in Crete, Greece, identify the Candida species involved and determine their susceptibility to antifungals. Over a 6-year period (2012-2017), 10 256 symptomatic women with vaginitis were evaluated. Isolation of yeasts was performed on Sabouraud dextrose agar with chloramphenicol, and the isolates were identified using the API 20 C AUX and/or the Vitek 2 YST card. Susceptibility of the isolates to amphotericin, fluconazole, voriconazole and flucytosine was determined by the Vitek 2 automated system. The results were interpreted according to Clinical and Laboratory Standards criteria. Vaginal swab cultures of 1217 (11.9%) women yielded Candida species. Recurrent VVC was documented in 62 (5.1%) of them. Candida albicans was the most frequently isolated species (75.6%), followed by Candida glabrata (13.6%). Overall, resistance rates to amphotericin B, fluconazole, voriconazole and flucytosine were 0.2%, 6.6%, 1.4% and 2.1%, respectively. Fluconazole resistance of C. albicans significantly increased in the second period of the study (2015-2017) (P = 0.031). This study demonstrated that VVC is a common infection among women in our region, with C. albicans being the predominant species involved. Although resistance to antifungals was infrequent, resistance to fluconazole among C. albicans isolates was found to significantly increase with time. Continued surveillance of changes in species distribution and susceptibility to antifungals are necessary to guide treatment.

Prevalence and antimicrobial susceptibility of Ureaplasma species and Mycoplasma hominis in Greek female outpatients, 2012-2016.

Mycoplasma hominis and Ureaplasma species are opportunistic pathogens associated with urogenital infections, complications during pregnancy and postpartum infections. Appropriate empirical antimicrobial treatment is necessary to achieve an optimal therapeutic outcome. This study evaluated the prevalence and the antimicrobial susceptibility of Mycoplasma hominis and Ureaplasma spp. isolated from 1,008 endocervical samples of outpatients in Crete, Greece, during a five-year period (2012-2016), using the commercially available Mycoview kit (Zeakon diagnostics, France). Ureaplasma spp. was isolated from 116 patients (11.5%), M. hominis from 6 (0.6%), while coinfection with both mycoplasmas was demonstrated in 17 (1.7%). All Ureaplasma strains were susceptible to josamycin and doxycycline. Doxycycline, minocycline and ofloxacin were the most potent antibiotics against M. hominis. Docycycline was proved the most active and is still the drug of choice for the treatment of genital mycoplasma infections. Local surveillance to monitor changes in antimicrobial susceptibilities is necessary to guide treatment strategies.

The Evolving Epidemiology of Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Strains Isolated from Adults in Crete, Greece, 2009-2016.

BACKGROUND: Pneumococcal disease is a major cause of morbidity and mortality worldwide, especially in patients with comorbidities and advanced age. This study evaluated trends in epidemiology of adult pneumococcal disease in Crete, Greece, by identifying serotype distribution and antimicrobial resistance of consecutive Streptococcus pneumoniae strains isolated from adults during an 8-year time period (2009-2016) and the indirect effect of the infant pneumococcal higher-valent conjugate vaccines 10-valent pneumococcal conjugate vaccine (PCV10) and 13-valent pneumococcal conjugate vaccine (PCV13). MATERIALS AND METHODS: Antimicrobial susceptibility was performed by E-test and serotyping by Quellung reaction. Multidrug resistance (MDR) was defined as non-susceptibility to penicillin (PNSP) combined with resistance to ≥2 non-ß-lactam antimicrobials. RESULTS: A total of 135 S. pneumoniae strains were isolated from adults during the study period. Twenty-one serotypes were identified with 17F, 15A, 3, 19A, and 11A, being the most common. The coverage rates of PCV10, and PCV13 were 17.8% and 37.8%, respectively. PCV13 serotypes decreased significantly from 68.4% in 2009 to 8.3% in 2016 (P = 0.002). The most important emerging non-PCV13 serotypes were 17F, 15A, and 11A, with 15A being strongly associated with antimicrobial resistance and MDR. Among all study isolates, penicillin-resistant and MDR strains represented 7.4% and 14.1%, respectively. Predominant PNSP serotypes were 19A (21.7%), 11A (17.4%), and 15A (17.4%). Erythromycin, clindamycin, tetracycline, trimethoprim-sulfamethoxazole, and levofloxacin resistant rates were 30.4%, 15.6%, 16.3%, 16.3%, and 1.5%, respectively. CONCLUSION: Although pneumococcal disease continues to be a health burden in adults in Crete, our study reveals a herd protection effect of the infant pneumococcal higher-valent conjugate vaccination. Surveillance of changes in serotype distribution and antimicrobial resistance among pneumococcal isolates are necessary to guide optimal prevention and treatment strategies.

Resistance phenotypes and susceptibility of contemporary Serratia isolates in the university hospital of Crete, Greece.

OBJECTIVE: To study changes in the susceptibility of Serratia spp. in Crete, Greece (2010-2015). METHODS: Non-duplicate isolates were examined using automated systems. Phenotypic confirmatory tests were applied. RESULTS: Three hundred and seventy-eight Serratia spp. were analyzed. Serratia marcescens (88.3%) was the predominant species. Fluoroquinolones (97.9%), carbapenems (97.4%) and fosfomycin (97.4%) were the most active followed by amikacin (95.5%), piperacillin/tazobactam (94.7%), and trimethoprim/sulfamethoxazole (94.4%). The activity of 3rd and 4th generation cephalosporins was 87-88.6%. The distribution of multi-drug resistant (MDR) strains varied, with a trend towards increasing frequency. ESBL (7.9%), carbapenemase (2.9%), AmpC (2.1%) and aminoglycoside modifying enzyme (10.6%) production were the commonest resistant phenotypes. CONCLUSION: The susceptibility of Serratia spp. varied during the study period a trend towards decreasing susceptibility, especially for non-carbapenem ß-lactams and aminoglycosides.