EVALUATION OF REDUCED SUSCEPTIBILITY TO VANCOMYCIN AMONG MRSA STRAINS ISOLATED FROM CLINICAL SPECIMENS

WOS: 000277896300021PubMed: 20549970In this study, a total of 390 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from clinical specimens between April 2004 and June 2008, in a university hospital in Zonguldak (located at Black Sea region), Turkey, were evaluated retrospectively for reduced susceptibility to vancomycin Brain heart infusion (BHI) plates containing 4 and 6 mu g/ml of vancomycin were used to screen for vancomycin intermediate S aureus (VISA) strains Additionally, vancomycin minimal inhibitory concentrations (MIC) of the isolates were determined by agar dilution method No growth was observed on the screen plates after 24 and 48 hours of incubation None of the isolates revealed MIC values equal to or higher than 2 mu g/ml, MIC(90) and MIC(50) values were 1 mu g/ml Although VISA isolates were not detected in this study, no data was obtained for heterogeneous VISA isolates since macro-E test or population analysis were not performed It was concluded that systematic surveillance of MRSA isolates is of particular importance to investigate the presence of VISA/hVISA isolates which may lead to treatment failures and hospital epidemic

Investigation of in-vitro susceptibility of multidrug-resistant Acinetobacter baumannii strains isolated from clinical specimens to tigecycline

The management of infections due to A. baumannii is difficult because of rapidly developing resistance, however, tigecycline, a glycylcycline antimicrobial, is in use for several years. In the present study, it was aimed to determine the susceptibility rates of A. baumannii to tigecycline. A total of 90 A. baumanniisolates were tested using three methods such as disk diffusion, broth microdilution, and E-test. The MIC50and MIC90 values and the MIC range were found as 2 μg/ml, 4 μg/ml, and 0.1-8 μg/ml by microdilution; and 2 μg/ml, 6 μg/ml, and 0.1-12 μg/ml by E-test, respectively. There were a few major errors as well as the minor rates were all high as between 35.7%-46.7%. The accuracy rates between the methods were low as 53.3% (48/90) between disk diffusion and E-test, 51.1% (46/90) between disk diffusion and microdilution, and 60.0% (54/90) between E-test and microdilution. In the ROC curve analysis, an inhibition zone diameter of susceptibility breakpoint of 21.5 mm had sensitivity between 68.8%-88.9%; specificity between 81.9%-87.9%; and accuracy between 80.0%-83.33%. An analysis based on EUCAST’s non-species breakpoints, the MIC tests showed higher accuracy with a rate of 96.7%, however, performance of disk diffusion got worse as lower than 25%. In conclusion, we showed that the reliability of the methods even did not remain as high as the past. Our study presented that none of three methods revealed reliable results in determination of susceptibility of A. baumanni to tigecycline, so the clinical response should be followed up carefully in such cases

Comparison of classical methods versus BACTEC blood culture system for culture of normally sterile body fluids

Background — Presence of microorganisms in sterile body sites leads to life-threatening infections. For early and accurate diagnosis of those infections, cultures of the sterile fluids have to be done. These cultures can not always detect the causative agents due to insufficent number or fastidious growing of the probable microorganisms in the material. Objectives — In this study, it was aimed to compare sterile body fluid cultures which had been processed with both conventional culture methods and BACTEC automatized blood culture system retrospectively. Material and Methods — A total of 138 body fluid cultures were compared retrospectively from the laboratory records. Results — Amongst the specimens, 122 cultures were negative. Nine of the rest 16 specimens were positive with both culture methods and seven cultures were positive with BACTEC only. None of the specimens which were negative in BACTEC system revealed positive with the conventionel method. BACTEC detected significantly higher number of positivity (P<0.001). No significant difference was found between the methods due to contamination (P=0.183). Conclusion — In conclusion, our study shows that inoculation of the sterile body fluid specimens into blood culture bottles and incubation of them in BACTEC system as well as culturing with conventional methods increase the detection rate of probable causative agents

Is Haemophilus influenzae better satellite for Enterococcus faecalis?

Background — Haemophilus influenzae can grow on blood agar media with Staphylococcus aureus which can provide factor V as it is called “Satellite phenomenon”. Objectives — In this study we tested and compared three different beta-haemolytic genus including three Staphylococcus aureus, three coagulase-negative staphylococci, and two Enterococcus faecalis strains in order to determine an alternative microorganism to be used for satellite test to identify H. influenzae conventionally. Materials and Methods — We used suspensions of H. influenzae in two different tribudities as 0.5 and 4 McFarland for each strain. Five totally-blinded reviewers examined the test results and scored both the colony sizes of H. influenzae and the diameter of the growth-zone. The sum of the scores for the colony sizes and the growth-zones were determined as “total diagnostic score” (TDS) as being between 0-6 points for each test. Results — A total of 320 test scores were analysed. The mean TDS of E. faecalis group was significantly higher than the other groups (p<0.001). In the S. aureus group, 23 (19.2%) tests had 0 points as TDS; but in enterococci group no isolates had lower scores than 3 points. In enterococci group, the rate of isolates which had 5 or 6 points was 77.5% (62/80); but in S. aureus group no isolate had higher than 4 points. Conclusions — Our study shows that using a beta-haemolytic E. faecalis strain will provide significantly more accurate results and will significantly reduce false-negative results for satellite test instead of S. aureus, which is particularly proposed to be used

A Case of Giant Hepatic Hydatid Cyst Infected with Morganella morganii and the Literature Review

Hydatid cyst disease is a common worldwide zoonosis. Most of the cysts are located in the liver. Abscess formation due to infection of the cyst is an important complication. M. morganii, a Gram-negative Bacillus, is a quite rare cause of liver abscess. A 77-year-old woman was admitted to hospital with complaints of fever, chills, nausea, vomiting, loss of appetite, and abdominal pain located in the right-upper quadrant. Her history was positive for hepatic hydatid cyst disease ten years ago. Physical examination revealed a painful mass filling the right-upper quadrant and extending down to umbilicus. Indirect hemagglutinin test for hydatid cyst was positive at a titer of 1/320. Giant liver abscess due to infected hydatid cyst was found in computed tomography scan. Surgeons performed cystectomy and cholecystectomy. Cefazoline, cefuroxime, and metronidazole were administered empirically, but all the three agents were replaced with intravenous ceftriaxone after M. morganii was isolated from the cultures of the abscess material. Clinical signs of the patient resolved at the second week of treatment, and she was discharged

Is rapid antibacterial susceptibility testing medium reliable for routine laboratory practices?

Objective: Early detection of antibiotic susceptibility profile of the isolates has critical importance in terms of immediate beginning of the appropriate treatment and increasing of treatment success, such as meningitis, bacteriemia and sepsis. In the present study, it was aimed to compare the antibiotic susceptibility results of Quicolor (Salubris Inc., Massachusetts, USA) and standard disk diffusion method

Examination of the specific clinical symptoms and laboratory findings of Crimean-Congo hemorrhagic fever

Background & objectives: Crimean-Congo hemorrhagic fever (CCHF) is a fatal disease, caused by a tick-borne virus (Nairovirus), having a high mortality rate. The study was aimed to evaluate the risk factors, the presenting symptoms and findings of the patients with prediagnosis of CCHF disease, and to compare these variables between the CCHF-positive and CCHF-negative patients. It was also aimed to develop a scoring formula for the diagnosis of CCHF. Methods: In total, 281 patients who were admitted to the Sabuncuoglu Serafeddin Training and Research Hospital, Amasya, Turkey between 2011 and 2015 and were prediagnosed with CCHF based on the clinical symptoms, laboratory findings and risk factors were included in the study. The definitive laboratory diagnosis of patients with prediagnosis of CCHF was ensured via molecular and serological methods. In addition, a mathematical diagnostic scoring formula was developed for enhancing the laboratory results of CCHF. Results: The ratio of certain clinical symptoms such as fever (p<0.001), headache (p<0.001), widespread body pain (p<0.001), fatigue (p = 0.001), nausea and vomiting (p = 0.013) in CCHF-positive patients were found to be significantly higher compared to the ratio in CCHF-negative patients. In terms of laboratory findings such as presence of leucopenia (p<0.001), creatine kinase (CK) elevation (p<0.001), thrombocytopenia (p<0.001), aspartate aminotransferase/alanine aminotransferase (AST/ALT) elevation (p<0.001), lactate dehydrogenase (LDH) levels (p = 0.002), absence of abnormal findings on chest radiograph (p = 0.042), and the absence of anaemia (p = 0.007), the CCHF-positive patients had higher rates in comparison to CCHF-negative ones. Interpretation & conclusion: It was inferred that certain clinical symptoms and laboratory findings such as fever, headache, widespread body pain, fatigue, leucopenia, nausea, vomiting, high CK levels, thrombocytopenia, AST/ ALT elevation and elevated LDH levels are highly specific and are required to be considered in the definitive diagnosis of CCHF, particularly in regions where this infection is observed as endemic

Determination of the staphylococcal cassette chromosome in methicillin-resistant Staphylococcus aureus strains isolated from various clinical samples

KOSTAKOGLU, UGUR/0000-0002-4589-0962; SANDALLI, Cemal/0000-0002-1298-3687WOS: 000408494600002Aim - the present study aimed to detect mecA and staphylococcal cassette chromosome mec (SCCmec) types in methicillin-resistant Staphylococcus aureus (MRSA) isolates obtained from various clinical samples in two university hospitals. It was also aimed to make comparison amongst the isolates. Materials and Methods - A total of 99 MRSA strains isolated from various clinical samples between 2011-2015 were included in the study. Bacterial deoxyribonucleic acid (DNA) was extracted from Staphylococcus aureus strains using GF-1 DNA extraction Kit (Vivantis, Malaysia). mecA gene were detected, and SCCmec cassette types were determined by multiplex polymerase chain reaction (PCR) first, and following specific PCR. Specific MRSA strains such as COL type I, PER3 type Ia, and HU25 type IIIa were used as the quality control strains for optimization of multiplex PCR. the amplification products were electrophoresed using agarose gel electrophoresis in TAE buffer (mixture of tris base, acetic acid and ethylenediaminetetraacetic acid). Results - mecA gene was detected in 60 Staphylococcus aureus isolates, and these were identificated as MRSA. Amongst the MRSA strains, SCCmec type III was the most frequent cassette type (42 isolates, 70.0%). SCCmec type I was detected in 27 isolates (45.0%), type II was in 26 isolates (43.3%), and type V in 23 isolates (38.3%). Conclusion - in the present study, the most frequent cassette was detected as SCCmec type III in concordance with the studies conducted in Turkey and in some regions in the world. in conclusion, determination of epidemiological and molecular characteristics of MRSA strains has critical importance because of the difficulties in the treatment and of the nosocomial infections and epidemics they caused. the data obtained would contribute to the preventions in terms of epidemiology

Evaluation of emm gene types, toxin gene profiles and clonal relatedness of group A streptococci

The aim of this study is to evaluate antibiotic susceptibilities, emm gene types, toxin gene profiles and clonal relatedness of group A streptococci (GAS) isolates obtained from patients and carriers. A total of 79 clinical isolates from patients and 60 isolates from carriers were included in the study. Emm typing, toxin gene detection for speA, speB, speC, speG and smeZ genes and pulsed-field gel electrophoresis (PFGE) was performed. Twenty-one distinct emm types were detected; the most common types were emm12, emm89, emm1, emm77, emm4 and emm3. The detection rates of both emm types and the toxingenes didn't differ significantly between patients and carriers. The presence of speA and smeZ was significantly higher in emm1 and speG was significantly lower in emm4 when compared to the other emm types. The rate of clustering obtained with PFGE wasn't significantly different in patients and carriers. As a result, twelve of the 21 emm types detected in this study were covered by the 26-valent vaccine, constituting 77.7% of the emm typeable isolates; however the emm4 type which is one of the most common types in the present study is not among this coverage

Carriage of Class 1 and 2 Integrons in Acinetobacter baumannii and Pseudomonas aeruginosa Isolated from Clinical Specimens and a Novel Gene Cassette Array: bla(OXA-11)-cmlA7

SANDALLI, Cemal/0000-0002-1298-3687WOS: 000332131600005PubMed: 24506715The dissemination of antibiotic resistance genes between bacteria leads to serious problems in the treatment of infectious diseases. It has been shown that resistance genes can also be carried by the integrons. There are limited studies regarding the carriage of class 1 and 2 integrons in Acinetobacter baumannii and Pseudomonas aeruginosa clinical strains in Turkey. the aims of this study were to investigate the carriage rates of class 1 and class 2 integrons in A.baumannii and P.aeruginosa strains isolated from clinical samples in Abant Izzet Baysal University Hospital, and to characterize the antibiotic resistance gene cassettes in these integrons by sequence analyses. A total of 137 strains (77 A.baumannii and 60 P.aeruginosa) isolated from various clinical specimens (56% were sputum, 19% wound, 11% urine, 11% blood, 3% catheter), between March 2010-December 2012, were included in the study. the identification and antibiotic susceptibility tests of the isolates were performed by Vitek 2 Compact (bioMerieux, France) and BD Phoenix 100 (Becton Dickinson, USA) systems. the presence of integrons were screened by PCR method using specific primer pairs targeting class 1 (intil1) and 2 (intl2) integrase regions. All the samples that revealed integron amplification were subjected to DNA sequence analysis, both in the forms of cloned products and PCR amplicons. in the study, the highest susceptibility rates were found against colistin (96%) and tigecycline (78%) in A.baumannii, and against piperacillin/tazobactam (97%) and piperacillin (93%) in P.aeruginosa isolates. the highest resistance rate was determined for piperacillin/tazobactam (95%) in A.baumannii strains. the presence of intl1 gene was detected in 33% (26/77) of A.baumannii and 10% (6/60) of P.aeruginosa isolates. When variable regions in intl1 positive strains were amplified by PCR, eight (8/77, 10%) A.baumannii and three (3/60, 5%) P.aeruginosa strains were found to harbor antibiotic resistance gene cassettes. Intl2 gene was not detected in any of the isolates. Resistance to piperacillin/tazobactam, ceftazidime, cefepime, ceftriaxone and ampicillin/sulbactam was detected as the common resistance pattern in all integron-positive A.baumannii strains, whereas resistance to ceftazidime, gentamicin and ciprofloxacin was the common pattern in all integron-positive P.aeruginosa strains. DNA sequence analysis of variable regions of integrons indicated that two separate gene cassette arrays (aacC1-aadAl and aac(3)-1) were carried by A.baumannii strains, and two types of gene cassette arrays (bla(OXA-30)-aadA1 and bla(OXA-11)-cmlA7) were carried by P.aeruginosa strains. To our best knowledge, this is the first report of the gene sequence of bia(OXA-11)-cmlA7 defined in an integron gene cassette of P.aeruginosa