Colistin resistance causes substantial problems in the treatment of serious infections with carbapenem-resistant (CR) gram-negative bacteria. In this study, we report a fatal hospital outbreak from the spread of a pandrug-resistant Klebsiella pneumoniae clone. An outbreak investigation was conducted after consecutive isolation of nine CR-K. pneumoniae (CR-Kp) strains from eight patients in two intensive care units of a university hospital within 2 weeks. Carbapenem and colistin resistance genes were investigated with PCR, clonal relationships of isolates were studied with pulse-field gel electrophoresis, and multilocus sequence types were determined. The outcomes of the affected patients were analyzed. Genotyping showed a predominant CR-Kp clone consisting of seven strains from six patients. These strains were in ST11 type, an international high-risk clone. They were resistant to all antimicrobials, including colistin, and positive for NDM-1 and OXA-48 carbapenemases, but negative for plasmid-borne colistin resistance genes. One patient had colonization and the remaining five died due to the infection within mean 12 days. No environmental or staff links could be established, and the outbreak was stopped by augmenting infection-control measures. Colistin-resistant K. pneumoniae could clonally expand in the hospital setting, and this spread might be associated with high mortality due to the lack of an appropriate treatment option. Immediate implementation of infection-control measures may be the best way to limit fatal consequences of the spread of such incurable pathogens.

Carbapenems are the choice of treatment in infections caused by multidrug resistant Enterobacteriaceae. In recent years carbapenem-resistant Enterobacteriaceae isolates due to carbapenemases have been increasingly reported worldwide. Multicenter studies on carbapenemases are scarce in Turkey. The aim of this study was to determine the distribution of carbapenemases from different parts of Turkey as a part of the European Survey of Carbapenemase Producing Enterobacteriaceae (EuSCAPE) project. Beginning in November 2013, carbapenem-resistant isolates resistant to at least one of the agents, namely imipenem, meropenem, and ertapenem were sent to the coordinating center. Minimum inhibitory concentrations for these carbapenems were determined by microdilution tests following EUCAST guidelines. Production of carbapenemase was confirmed by combination disk synergy tests. Types of carbapenemases were investigated using specific primers for VIM, IMP; NDM, KPC and OXA-48 genes by multiplex polymerase chain reaction. In a six month period, 155 suspected carbapenemase-positive isolates were sent to the coordinating center of which 21 (13.5%) were E.coli and 134 (86.5%) were K.pneumoniae. Nineteen (90.5%) strains among E.coli and 124 (92.5%) strains among K.pneumoniae were shown to harbour at least one carbapenemase gene by molecular tests, with a total of 92.3% (143/155). Carbapenemases were determined as a single enzyme in 136 strains (OXA-48: 84.6%; NDM: 6.3%; VIM: 2.8%; IMP: 1.4%) and as a combination in seven isolates (OXA-48 + NDM: 2.1%; OXA-48 + VIM: 2.1%; VIM + NDM: 0.7%). KPC was not detected in any of the isolates. According to the microdilution test results, resistance to imipenem, meropenem and ertapenem in OXA-48 isolates were 59.5%, 52.9% and 100%, respectively. The combination disk synergy test was 100% compatible with the molecular test results. As most of the OXA-48 producing isolates were susceptible to meropenem but all were resistant to ertapenem, ertapenem seems to be the most sensitive agent in screening carbapenemases in areas where OXA-48 is prevalent and phenotypic combination tests can be useful in centers where molecular tests are not available.

Background: A limited number of antibiotics are recommended for the therapy of Stenotrophomonas maltophilia infections due to therapy difficulties caused by its numerous mechanisms of resistance. Objectives: In this study conducted over a period of approximately 5 years we aimed to determine resistance rates of S. maltophilia based on drug classification recommended by Clinical and Laboratory Standards Institute. Methods: A total of 118 S. maltophilia strains isolated from various clinical specimens between January 2006 and June 2012 were included in the study. BD Phoenixautomated microbiology system (Becton Dickinson, USA) was utilized for species level identification and antibiotic susceptibility testing. Results: Sixty seven of S. maltophilia strains were isolated from tracheal aspirate isolates, 17 from blood, 10 from sputum, 10 from wound and 14 from other clinical specimens. Levofloxacin was found to be the most effective antibiotic against S. maltophilia strains with resistance rate of 7.6%. The resistance rates to other antibiotics were as follows: chloramphenicol 18.2%, trimethoprim-sulfamethoxazole 20.3% and ceftazidime 72%. Conclusion:The study revealed that S. maltophilia is resistant to many antibiotics. The treatment of infections caused by S. maltophilia should be preferred primarily as levofloxacin, chloramphenicol, and TMP-SXT, respectively.

Objective. Recently, community and hospital-acquired infections with Staphylococcus aureus have increased and raised antibiotic resistant isolates. In this study, we aimed to evaluate the antibiotic resistance profile of S. aureus isolates over several years in various clinical specimens from our hospital. Materials and Methods. S. aureus strains from 2009 to 2014 were isolated from various clinical samples at Yuzuncu Yil University, Dursun Odabas Medical Center, Microbiology Laboratory, and their antibiotic susceptibility test results were retrospectively investigated. The isolates were identified by conventional methods, and antibiotic susceptibility tests were performed by the Phoenix (Becton Dickinson, USA) automated system method according to Clinical and Laboratory Standards Institute (CLSI) standards. Results. A total of 1,116 S. aureus isolates were produced and methicillin-resistant S. aureus (MRSA) to 21% of all S. aureus isolates between 2009 and 2014. According to the results of susceptibility tests of all isolates of S. aureus, they have been identified as sensitive to vancomycin, daptomycin, linezolid, and levofloxacin. While the resistance rates to nitrofurantoin, quinupristin-dalfopristin, and trimethoprim-sulfamethoxazole were determined as 0.3%, 2.4%, and 6%, respectively, resistance rates to penicillin, erythromycin, rifampicin, gentamicin, and clindamycin were determined as 100%, 18%, 14%, 14%, and 11%, respectively. The highest percentage of methicillin resistance was determined as 30% in 2009, and the resistance was determined to have decreased in subsequent years (20%, 16%, 13%, 19%, and 21%) (p < 0.001). Conclusion. Currently, retrospective evaluations of causes of nosocomial infection should be done periodically. We think that any alteration of resistance over the years has to be identified, and all centers must determine their own resistance profiles, in order to guide empirical therapies. Reducing the rate of antibiotic resistance will contribute to reducing the cost of treatment.

Purpose: Brucellosis is a worldwide zoonotic disease and still constitutes a major public health problem. In this study, we aimed to identify biovars of Brucella strains isolated from clinical specimens taken from brucellosis patients from the Eastern Anatolia region as well determine the susceptibility of these isolates to tigecycline and azithromycin, drugs that may serve as alternatives to the conventional drugs used in the therapy.Materials and methods: Seventy-five Brucella spp. isolates were included in the study. All strains were identified by both conventional and molecular methods. Brucella Multiplex PCR kit (FC-Biotech, Code: 0301, Turkey) and B. melitensis biovar typing PCR kit (FC-Biotech, Code: 0302, Turkey) were used for molecular typing. Antimicrobial susceptibilities of all strains were determined by E-tests.Results: By conventional biotyping, 73 strains were identified as B. melitensis biovar 3 and two strains as B. abortus biovar 3. Molecular typing results were compatible with conventional methods. The MIC50 and MIC90 values of doxycycline were 0.047 and 0.094; tigecycline 0.094 and 0.125; trimethoprim/sulfamethoxazole 0.064 and 0.19; ciprofloxacin 0.19 for both; streptomycin 0.75 and 1; rifampin 1 and 2 and azithromycin 4 and 8. According to the MIC values, doxycycline was found to be the most effective antibiotic, followed by tigecycline, trimethoprim-sulfamethoxazole and ciprofloxacin.Conclusion: Currently recommended antibiotics for the treatment of brucellosis such as doxycycline, rifampin, streptomycin, trimethoprim-sulfamethoxazole and ciprofloxacin were found to be still effective. While our results showed that tigecycline can be used an alternative agent in the treatment of brucellosis, azithromycin has not been confirmed as an appropriate agent for the treatment.