Türkiye ranks among the highest in antibiotic consumption within OECD countries and faces growing challenges from multidrug-resistant uropathogens. Nationwide, resistance-guided treatment data remain scarce. The main objective of this work is to provide a comprehensive nationwide data on antibiotic resistance patterns among uropathogens to guide treatment options in urinary tract infections (UTIs). A multicenter, retrospective observational study was conducted between 2021 and 2023 across 11 centers from 8 provinces representing all major geographical regions of Türkiye. Uropathogens isolated from adult patients with UTIs were analyzed to assess temporal trends and regional variability in antimicrobial resistance. In outpatients, resistance to commonly used oral agents (amoxicillin–clavulanate, ciprofloxacin) frequently exceeded 30

Abstract Acquired aplastic anemia (AA) is a life-threatening bone marrow failure disorder, and febrile neutropenia (FN) episodes in children with AA pose significant risks due to infections. The study aimed to investigate the incidence, types, and outcomes of infections during FN episodes in pediatric AA patients. This single-centre retrospective cohort study included 39 pediatric patients with AA diagnosed between January 2004 and January 2024. Data from medical records, including clinical characteristics, laboratory findings, immunosuppressive therapy details, microbiological results, and infection outcomes, were analyzed. Infection sources, pathogens, and outcomes were assessed, and statistical analysis was performed to identify risk factors for infections and mortality. Twenty-five patients were male (64.1%), with a median age of 12,05 years (interquartile range : 6 to 14,94y). A total of 152 FN episodes were evaluated, with 87.1% of patients experiencing at least one episode [median, 4.15 (range:1–15)]. 58 (38.1%) episodes were classified as microbiologically documented infections(MDI); bloodstream infections(BSIs) (n = 36, 23.6%) were the most common, including central line-associated BSIs (CLABSIs) (n = 29, 19%). Among BSIs, 81% (29/36) were caused by Gram-negative (GN) bacteria and 19% (7/36) by Gram-positive (GP) bacteria. The most frequently isolated microorganism was coagulase-negative Staphylococci (n = 13, 8.55%), followed by Escherichia coli (n = 12, 7.89%) with a high extended-spectrum beta-lactamase (ESBL) positivity rate (69%). Fungal infections (proven+probable) were identified in 8 episodes (5.26%), and viral infections in 3 episodes (1.97%). Rabbit-derived antithymocyte globulin (RD-ATG ) was found to be significantly associated with BSIs in both univariable and logistic regression analyses (OR 8.8, 95% CI 1.692–45.761, p = 0.006). The attributable mortality (AM) of infection episodes was 5.2%. In multivariate analysis, bacterial BSIs, particularly GN- BSIs and those receiving RD-ATG, were significant predictors of increased mortality (p < 0.05). GN bacterial infections and fungal infections negatively affected survival. RD-ATG therapy was identified as a risk factor for increased infection frequency and severity, particularly in cases of BSIs and GN bacteremia. Timely and appropriate antimicrobial treatment is crucial, and the high mortality rates associated with severe infections underscore the importance of early detection and intervention.

Background: Carbapenem-resistant Enterobacterales (CRE) are a major therapeutic challenge, particularly in settings where metallo-β-lactamases are prevalent. Aztreonam-avibactam (AZA) may provide activity against metallo-β-lactamase-producing isolates, whereas ceftazidime-avibactam (CZA) has limited activity against the isolates that harbor these enzymes. This study aimed to evaluate the in vitro activity of aztreonam-avibactam and ceftazidime-avibactam against invasive carbapenem-resistant Enterobacterales isolates and to characterize the distribution of carbapenemase genes in a tertiary-care center in Türkiye. Methods: A total of 100 non-duplicate CRE isolates recovered from blood cultures and sterile body fluids between January 2024 and January 2026 were included. Species identification and routine antimicrobial susceptibility testing were performed using MALDI-TOF MS and an automated system. CZA and AZA MICs were determined by gradient diffusion testing, whereas CZA-aztreonam synergy was assessed separately using a disk/gradient diffusion-based method. Carbapenemase genes were detected by real-time PCR. Whole-genome sequencing was performed for the two AZA-resistant Escherichia coli isolates. Results: The isolate collection was dominated by Klebsiella pneumoniae (87.0%), and most isolates were recovered from blood cultures (80.0%). CZA susceptibility was observed in 31.0% of isolates, with MIC50/90 values of 256/256 mg/L. In contrast, AZA showed high in vitro activity, with 98.0% of isolates categorized as susceptible and MIC50/90 values of 0.25/0.50 mg/L. CZA-aztreonam synergy was detected in 98.0% of isolates. Qualitative CZA-aztreonam synergy testing did not fully concord with direct AZA MIC-based susceptibility categorization: one AZA-resistant isolate showed a positive synergy result, whereas one synergy-negative isolate remained AZA-susceptible. Carbapenemase genes were detected in 99.0% of isolates; blaNDM was the most frequent gene (81.0%), followed by blaOXA-48 (72.0%), blaKPC (14.0%), and blaVIM (4.0%). The most common carbapenemase profile was blaNDM + blaOXA-48 (62.0%). blaNDM carriage was strongly associated with CZA resistance, and CZA MICs were significantly higher among blaNDM-positive isolates. The two AZA-resistant E. coli isolates belonged to ST500 and ST410, and both carried a YRIK insertion in PBP3; one of them additionally showed ompF disruption associated with a 4 bp insertion. Conclusions: AZA demonstrated potent in vitro activity against invasive CRE isolates in this setting, whereas CZA activity was substantially limited, likely reflecting the high prevalence of blaNDM and frequent carbapenemase co-carriage. These findings support the potential value of AZA in regions with emerging metallo-β-lactamase predominance and highlight the importance of local molecular surveillance to guide antimicrobial strategies.

Background:Methicillin-Resistant Staphylococcus aureus (MRSA) is a major clinical challenge due to its biofilm-forming ability. Innovative therapeutic strategies are essential to prevent bacterial attachment and disrupt biofilm structures. This study investigates the potential of CRISPR technology as a tool to combat resistance by targeting the biofilm-associated genes icaA, icaD, and bap in MRSA. Methods:Specific guide RNAs were cloned into pCasSA plasmids to target the icaA, icaD, and bap genes. Gene expression changes were quantified using quantitative PCR (qPCR), and mutations were confirmed through Sanger sequencing. Biofilm formation was assessed by crystal violet assay, and antimicrobial susceptibility was evaluated by broth microdilution and disk diffusion methods. Results:qPCR analyses confirmed significant reductions in gene expression: 3.3-fold for icaA, 2.3-fold for icaD, and 1.7-fold for bap. Sanger sequencing confirmed point mutations and indels within the target regions of genes. Biofilm formation decreased markedly, with 6-fold in icaA-mutant, 5.6-fold in icaD-mutant, and threefold in bap-mutant strains. MIC values were substantially reduced in all mutant strains: oxacillin MIC decreased 64-fold, 16-fold, and 4-fold in icaA-, icaD-, and bap-mutants, respectively, and ciprofloxacin MIC decreased 64-128-fold. Zone diameters for cefoxitin, norfloxacin, and gentamicin increased up to twofold across all mutant strains. All strains remained resistant according to EUCAST clinical breakpoints. Conclusion:This study demonstrates that CRISPR-Cas9-mediated disruption of biofilm-associated genes is an effective strategy for inhibiting biofilm formation in MRSA. Targeted disruption of icaA, icaD, and bap significantly reduced biofilm formation and partially attenuated antimicrobial resistance phenotypes. These findings highlight the potential of pathogen-specific CRISPR-based anti-virulence strategies as complementary approaches for the treatment of biofilm-associated infections.

This study aims to elucidate the classification, clinical presentation, follow-up, and treatment outcomes of elderly patients diagnosed with infectious keratitis. This retrospective single-center analysis, conducted at a tertiary ophthalmology center (Ege University Medical Faculty Hospital, Department of Ophthalmology, Izmir, Turkiye), included 317 patients aged ≥ 60 years diagnosed with infectious keratitis between January 2012 and January 2025. Microbiological culture results, clinical course, comorbidities, treatments, and outcomes were evaluated. The female-to-male ratio was 0.89 and the mean age was 72.1 ± 7.23 years (range: 60–96 years). Positive culture results were identified in 128 (40.4

Introduction: The increasing prevalence of carbapenem-resistant Klebsiella pneumoniae (CR-Kp) limits effective treatment options. The aim of this study was to evaluate the susceptibility patterns of CR-Kp strains isolated from urine cultures to oral treatment options recommended by the Infectious Diseases Society of America guidelines, and ceftazidime-avibactam. Additionally, clinical data and outcomes of patients diagnosed with CR-Kp urinary tract infections (UTI) who were treated with fosfomycin sodium-including therapy regimens (FSITR) were analyzed. Methodology: This retrospective cohort study included adult patients with urine culture-proven CR-Kp between March 2016 and October 2022. Demographic and clinical data, antibiotic susceptibility, treatment outcomes, and one-month mortality (OMM) were evaluated. Results: A total of 179 patients were included. The susceptibility to fosfomycin tromethamol, nitrofurantoin, and co-trimoxazole (TMP-SMX) were (33.7%; 55/163), (7.7%; 13/167), and (11.1%; 20/179), respectively. All strains were resistant to ciprofloxacin. The susceptibility data compared until 2020 (pre-COVID-19) and afterwards, revealed TMP-SMX susceptibility (4.9% vs 24.1%, p = 0.0001) increased significantly. Susceptibility data for ceftazidime-avibactam were available for 22 isolates and 59% of the isolates were sensitive. OMM of the 179 patients with CR-Kp in urine cultures was 37.4% (67/179). There were 9 FSITR cases. Among those, microbiological eradication was achieved in 87.5% (7/8) and OMM was 44.4% (4/9). Conclusions: Clinical experience may be feasible and needed to assess the efficacy of nitrofurantoin and TMP-SMX. Fosfomycin-including regimens may serve as a salvage treatment option for CR-Kp UTI in selected patients. However, the retrospective and single-center design of the study should be considered as a limitation.

Salmonella enterica may contribute to the spread of colistin resistance and play a significant role in transferring mcr genes to other clinically important bacterial pathogens. Colistin resistance in Salmonella enterica arises from mcr genes and/or modifications of lipopolysaccharides caused by mutations in the pmrA/pmrB encoding two-component system. In this study, we evaluated the adhesion and invasion capabilities of colistin-susceptible and -resistant Salmonella enterica, as well as the relationship between colistin resistance and pmrA/pmrB mutations. Ninety-one clinical isolates from 2016 to 2019 were analyzed for colistin susceptibility testing, serotyping, PCR analysis of 16S rRNA, plasmid-mediated mcr genes, and mutations in pmrA and pmrB. Adhesion, invasion, and macrophage survival assays were conducted, considering serotype and colistin susceptibility. The majority of isolates were from pediatric emergency cases (n = 59, 64.84

Yersinia pseudotuberculosis is a rare pathogenic organism in humans and is encountered mostly in patients with acquired or hereditary iron overload. This case report presents such a case with no known risk factors for iron overload, except heterozygous mutations in MPEG1 and HFE genes, while presenting the first patient with Y. pseudotuberculosis liver abscess in Turkiye. Here we present a 63-years-old male with known long-standing hypertension, type 2 diabetes, peripheral artery disease and chronic kidney disease presenting with right upper quadrant pain, nausea, vomiting and fever, whose imaging studies revealed multiple liver abscesses. While investigating the etiology, Yersinia pseudotuberculosis growth was observed in his abscess aspiration material and blood culture. Genetic analysis conducted after the detection of a ferritin level of 13725 mu g/L, showed a heterozygous H63D mutation in HFE. Consequent whole-exon-sequencing reported an additional heterozygous p. Thr73Ala mutation in MPEG1. Even though, Y. pseudotuberculosis is detected mostly in patients with primary hemochromatosis, even heterozygous carriers of hemochromatosis may present clinically if concomitant comorbidities exist and may pose a challenge not only to clinicians but also to laboratory diagnosticians.

Aim: Septic arthritis among adults most commonly affects the knee, hip, and shoulder joints, and is often treated with urgent surgical intervention. Although certain laboratory findings are considered definitive for diagnosis, a broad range of clinical and laboratory parameters can be observed. In this study, we evaluated the clinical and laboratory characteristics of adult patients who underwent joint aspiration with a preliminary diagnosis of septic arthritis. Materials and Methods: A retrospective chart review was conducted to identify patients who underwent knee joint arthrocentesis for suspected septic arthritis between January 2020 and March 2024. Demographic data, synovial fluid analyses, laboratory parameters, physical examination findings, empirically initiated and culture-guided antibiotic treatments were recorded. Results: Total of 159 patients included. Of those, 81 (50.9%) were male and 78 (49.1%) were female. Median age was 58 years (range 18-88). Mean WBC count was 10,366/mL (SD+ 4051.1), and the mean CRP was 106.84 mg/L (SD +87.2). 71 (44.6%) were clinically diagnosed with septic arthritis. Positive cultures were obtained in 36 patients. The most frequently isolated organisms were Staphylococcus aureus (n=20). Among the physical examination findings, pain was the most frequently observed, present in 92 of 159 patients (57.8%). Swelling was the second most common finding, identified in 90 patients (56.6%), followed by limitation of movement in 68 patients (42.7%). Discussion: Septic arthritis of the knee may present with a wide spectrum of clinical and laboratory findings. Diagnosis should rely on the synthesis of these parameters and remain essentially clinical, rather than being based on a single variable.

To the Editors: Patients receiving interleukin-6 receptor inhibitors, including tocilizumab (TCZ), have been shown to exhibit increased susceptibility to infections, including mycobacterial and opportunistic pathogens.1 To our knowledge, there are limited data regarding severe infections in patients with systemic diseases treated with TCZ, except for rheumatoid arthritis and some studies on giant cell arteritis.2 Here, we present a case of a 6-year-old girl with rituximab-refractory autoimmune encephalitis who developed mastoiditis, meningitis, ventriculitis and sinus venous thrombosis caused by Streptococcus pneumoniae while receiving TCZ therapy. A 6-year-old female presented with vomiting, fatigue, swelling and redness behind the auricle with a protrusion, which developed during treatment on amoxicillin-clavulanate for suspected otitis media. She had a history of neuroblastoma, was treated with chemotherapy and surgery and was diagnosed with paraneoplastic opsoclonus-myoclonus ataxia syndrome, anti-Hu encephalitis and epilepsia partialis continua. Despite using antiepileptics and rituximab, her seizures were uncontrolled, prompting the initiation of TCZ 2 years ago. The last dose was administered 2 weeks prior to hospitalization. The initial diagnosis included acute sinusitis, otitis and mastoiditis, but follow-up revealed altered consciousness, nuchal rigidity and positive Kernig and Brudzinski signs. Brain magnetic resonance imaging (MRI) showed auto-mastoiditis, thrombosis in the left sigmoid sinus and dense material in both lateral ventricles, suggestive of ventriculitis (Fig. 1A and D).FIGURE 1.: MRI findings of ventriculitis. A: At the diagnosis. B: The third week of treatment. C: The seventh week of treatment. D: At the diagnosis, thrombus in the left sigmoid sinus. E: The third week of treatment, regression of the thrombus and partial recanalization. F: The seventh week of treatment, regression of the thrombus and partial recanalization.Laboratory results revealed an elevated white blood cell count of 37,850/µL and a neutrophil count of 33,160/µL. C-reactive protein was measured at 17.2 mg/L and procalcitonin at 1.36 µg/L. The erythrocyte sedimentation rate was within normal limits at 19 mm/hour. Cerebrospinal fluid analysis showed purulent fluid with 6000 white blood cells/µL, 5009 neutrophils/µL, low glucose (<2 mg/dL) and high protein (286 mg/dL). Polymerase chain reaction confirmed S. pneumoniae though no growth was observed in the culture. Intravenous vancomycin (60 mg/kg/day), cefotaxime (300 mg/kg/day) and low-molecular-weight heparin were initiated. Within 3 days, meningeal signs improved, and the patient regained consciousness. During the first week, she underwent a left simple mastoidectomy and ventilation tube placement. Postoperatively, cefotaxime was replaced with cefepime (150 mg/kg/day). In the third week of follow-up, the MRI showed a 2-cm abscess-like collection extending from the mastoidectomy site, with regression of ventriculitis and meningitis, and partial recanalization of the left sigmoid sinus (Fig. 1B and E). Vancomycin was switched to linezolid (30 mg/kg/day) due to the development of an allergy. By the fourth week, a follow-up lumbar puncture revealed clear cerebrospinal fluid with normal glucose and protein levels, and no pathogens were detected in the polymerase chain reaction or culture. A comparative MRI showed complete resolution of signal enhancement in the cerebral and cerebellar sulci with no evidence of pus or hydrocephalus and a regressed abscess in the left mastoid at the seventh week (Fig. 1C and F). The patient completed 52 days of intravenous treatment and was discharged, with a plan to continue low-molecular-weight heparin therapy for a total of 3 months. Following consultation with pediatric neurology and immunology, TCZ therapy was temporarily discontinued. Her baseline immunologic tests were normal, and follow-up on the whole-exome sequencing result is ongoing. In children treated with TCZ for juvenile idiopathic arthritis, the infection rate was reported as 151.4 per 100 patient-years, with serious infections occurring at a rate of 5.2 per 100 patient-years.3 In pediatric studies, serious infections after receiving TCZ primarily involve the skin and respiratory tract.4 However, data about severe central nervous system involvement like in our case are lacking. In conclusion, close monitoring is crucial for patients receiving TCZ, especially those with significant systemic inflammation. Prophylactic vaccinations, such as pneumococcal vaccination, should be administered before starting TCZ therapy when possible.

OBJECTIVE:This study evaluated the diagnostic performance of the FilmArray GI Panel multiplex polymerase chain reaction (PCR) compared to conventional stool culture (CSC) and microscopic stool analysis in children with bacterial acute infectious gastroenteritis (AIG) in the emergency department (ED). It also assessed the impact of PCR use on clinical decision-making, antibiotic stewardship, and ED workflow. METHODS:A retrospective analysis was conducted in a tertiary pediatric ED. Children diagnosed with AIG who underwent CSC, microscopy, and multiplex PCR were included. Data on demographics, clinical findings, diagnostic results, antibiotic prescriptions, and patient outcomes were collected. Diagnostic performance metrics-sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)-were compared. RESULTS:Among 257 pediatric patients, enteropathogens were detected in 31.9% via CSC and 39.3% via multiplex PCR. PCR showed superior sensitivity (96.2%) and NPV (97.4%) compared to CSC. The median turnaround time for PCR (7.9 h) was significantly shorter than for CSC (47.5 h, p < 0.001). Antibiotic use was significantly lower in PCR-negative cases (p < 0.001), and ED length of stay was also reduced. CONCLUSION:The FilmArray GI Panel offers improved sensitivity and faster results than conventional methods, enhancing diagnostic accuracy and reducing unnecessary antibiotic use. Its integration in ED protocols can support antimicrobial stewardship and streamline care.

Background/Aim: To compare the effectiveness ceftaroline-rifampicin (CR) and vancomycin-rifampicin (VR), against methicillin-resistant Staphylococcus aureus (MRSA) in a rabbit meningitis model, to compare the effects on brain tissues in terms of inflammation and apoptosis and to test the antibiotics via in vitro time-kill and synergy tests. Method: Meningitis was induced using MRSA strain ATCC 43300. After 28 hours, the rabbits were split into three groups: control, VR, and CR. A CSF culture was taken at the start (T0) and end of treatment (EOT)-the 24th hour of treatment. At EOT, the animals' brain tissues were examined for inflammation and apoptosis. The study strain was tested for a 24-hour time kill assay. Results: At the EOT, statistically significant differences were observed between the treatment groups in terms of reducing the cerebrospinal fluid (CSF) bacterial count, achieving partial or complete treatment response, and exhibiting lower levels of neuronal apoptosis compared with the control group. However, there was no significant difference in all three parameters and in survival between the two treatment groups. The CR group exhibited a noticeable decrease in inflammation than the control group, but no significant difference was found between the control group versus VR and VR versus CR group. Rifampicin did not improve antibacterial efficacy in the in vitro time-kill assay. Conclusion: The CR arm showed better complete response and inflammation, but both treatments were similar in other parameters. CR combination was found as effective as VR combination for treating MRSA meningitis.

Background: In this study it was aimed to evaluate the efficacy and timing with technique of the source control for the subgroup of septic shock (SS) patients with intraabdominal infections (IAI) in a tertiary-care educational hospital. Methods: Patients who had SS with IAI and consulted by Infectious Diseases consultants between December 2013 and October 2022 in our centre were analyzed retrospectively. Results: A total number of 390 patients were included. Overall day-30 mortality (OMM) was 42.5% on day 3 while day 14 and 30 mortality rates were 63.3% and 71.3%, respectively. Source control by surgical or percutaneous operation was performed in 123 of 390 cases (31.5%) and mortality rate was significantly lower in cases that were performed source control at anytime during SS (65/123-52.8% vs 213/267-79.8%, p<0.001). In 44 of 123 cases (35.7%) source control was performed during the first 12 hours and mortality was significantly lower in this group versus others (24/44-54.5% vs 254/346-73.4%, p=0.009). On the other hand, female gender (p<0.001, odds ratio(OR)=1.714-5.054, 95%CI=1.714-5.054), diabetes mellitus (p= 0.014, OR=2.284, 95%CI=1.179-4.424), carbapenem-resistant Gram-negative etiology (p=0.011, OR=4.386, 95%CI=1.398-13.759), SOFA≥10 (p<0.001, OR=3.036, 95%CI=1.802-5.114), lactate >3 mg/dl (p<0.001, OR=2.764, 95%CI=1.562-4.891) and lack of source control (p=0.001, OR=2.796, 95%CI=1.523-5.133) were significantly associated with OMM in logistic regression analysis. Conclusions: Source control has a vital importance in terms of mortality rates for IAI related septic shock patients. Our study underscores the need for additional research, as the present analysis indicates that early source control does not manifest as a protective factor in logistic regression.

Objectives: Carbapenem-resistant A. baumannii is a common cause of nosocomial meningitis, and it presents a challenge in terms of treatment because of limited therapeutic options. Intravenous tigecycline has been considered a potential salvage therapy against multi-drug-resistant Acinetobacter baumannii. However, its effectiveness is limited by its poor ability to cross the blood-brain barrier. As an alternative treatment option, intrathecal tigecycline has shown promise with its minimal side effects and high concentration in cerebrospinal fluid.Methods: In this report, we present a series of four cases infected with multi-drug-resistant A. baumannii following neurosurgery and treated with intrathecal tigecycline, including antimicrobial therapy.Results: The rate of successful microbiological response was 2 out of 3 cases (66%) in whom microbiological response could be tested anytime during the intrathecal therapy, whereas the 30-day survival rate after treatment completion was 1/4 (25%).Conclusion: Although intrathecal tigecycline treatment has shown relative efficacy in achieving microbiological response, its impact on overall survival is still uncertain. Further studies involving larger groups of patients are necessary to evaluate the outcomes of intrathecal tigecycline therapy.

Introduction: Nosocomial meningitis may occur after procedures affecting the central nervous system or following traumatic injury. The causative infectious organism is commonly Staphylococcus aureus, a Gram-positive bacterium. The aim of the present study was to compare the effectiveness of two antibacterial agents, ceftobiprole and vancomycin, in an animal model of methicillin-resistant S. aureus (MRSA) meningitis. Method: The strain of MRSA used was ATCC 43300. The animals were divided into three groups and infected intracisternally with MRSA. Controls received no antibiotherapy while the ceftobiprole group received 25 mg/kg and the vancomycin group received 20 mg/kg intravenously. Blood and cerebrospinal fluid (CSF) samples were collected at three time points. All animals were euthanized at 73 h after start of treatment. Results: There was a significant difference (p < 0.05) between both treatment groups and the control animals at 24 h (drug trough) and 73 h (1 h after third dose) after start of treatment in terms of CSF bacterial levels. At 73 h, there was a significant difference in survival between the control group and the two treatment groups but no difference between the treated animal survival rates. Conclusion: Intravenous treatment with ceftobiprole and vancomycin appears to be equally effective in a rabbit model of MRSA meningitis.

BACKGROUND-AIM Herein, we aimed to evaluate and compare the efficacy and susceptibility patterns of tigecycline in MDR A.baumannii pneumonia (MDRABP) in a recent vs retrospective cohort. METHODS The outcome of adult (>18 years old) patients who were consulted by Infectious Diseases consultants due to culture proven MDRABP and treated with tigecycline between March 2016 and October 2023(Group B) was compared with a similar previously published retrospective cohort from our center(Group A, Published J Chemother. 2011 dec;23(6):345-9). Statistical analysis was performed via Chi square test and a p value less then 0.05 was considered significant. RESULTS There were total of 202 cases of MDRABP(72 patients in group a and 130 patients in Group B). Forty-seven and 81 cases were considered as VAP in group A and B, respectively. Tigecycline and netilmicin susceptibility were significantly less in group b(Table). C/S combination and tigecycline monotherapy were significantly more common in group A while any combination therapy, colistin, fosfomycin and polymyxin b combination were more common in group B (p<0.05 table). Group A EOT microbiologic eradication was significantly higher in the overall cohorts as well as HAP and VAP subgroups(Table). In the combined data of group A and B microbiological response was similar in tigecycline sensitive vs. intermediately-sensitive strains (41/94-43.6% vs.22/48-45.8% p:0.801). Not overall clinical success but clinical success in combination therapy subgroup was significantly lower in group B(Table). CONCLUSION Our findings show that tigecycline resistance rates in MDRABP increased during years. Microbiological eradication rates but not clinical outcomes decreased significantly.