Prevalence and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus in Foods of Animal Origin, Turkey.

In the present study, 175 coagulase-positive Staphylococcus (CPS) isolates recovered from samples of beef (n = 110), raw milk n = 56), and fish (n = 9) were analyzed for methicillin resistance using MIC and PCR assays. Methicillin-resistant (MR) Staphylococcus aureus (SA) isolates were then characterized using pulsed-field gel electrophoresis (PFGE). According to findings, 62 (35.4%) of the isolates (44 from beef, 9 from milk, and 9 from fish) were identified as S. aureus based on the presence of the nuc gene. MRCPS was detected in 18 (10.3%) of 175 CPS isolates based on the presence of the mecA gene. Among these isolates, 15 (24.2%) were MRSA: 4 (26.7%) from beef, 2 (13.3%) from milk, and 9 (60%) from fish. However, based on the MIC assay, 21 (12.0%) of the CPS isolates (1 from beef, 15 from milk, and 5 from fish) were MRCPS, indicating a discrepancy between the results of these two methods. The PFGE results indicated genetic heterogeneity of the isolates; six PFGE clusters were found. These results confirm that MRSA is present in foods of animal origin, which is a concern to human health, and indicate the importance of method selection for determination of methicillin resistance. The identity of MR isolates should be verified by PCR to obtain more reliable results.

[Investigation of the presence of class 1, 2, 3 integrons and their relationships with antibiotic resistance in clinical Stenotrophomonas maltophilia isolates]. / Klinik Stenotrophomonas maltophilia izolatlarinda sinif 1, 2, 3 integron varliginin ve antibiyotik direnci ile iliskilerinin arastirilmasi

Stenotrophomonas maltophilia is an opportunistic emergent pathogen causing hospital-acquired infections. It is resistant to majority of the broad spectrum antibiotics due to several mechanisms which significantly limit the treatment options. Although the relationship between integrons, mobile genetic elements which play role in transferring resistance genes, and the antibiotic resistance in different gram-negative bacteria have been investigated, the data are limited in Turkey especially for S.maltophilia. The aims of this study were to detect the presence of different classes of integrons and plasmids in clinical isolates of S.maltophilia and to investigate the antibiotic resistance profiles of those isolates. One hundred S.maltophilia strains isolated from various clinical samples (32 sputum, 25 tracheal aspirates, 9 urine and blood, 7 exudates and catheters, 4 sterile body fluids and wounds, 2 CSF, 1 conjunctiva) in our microbiology laboratory during January 2011-September 2012, were included in the study. The isolates were identified by VITEK2 Compact (BioMerieux, France) or Phoenix 100 (BD, USA) automatized systems, and the susceptibilities of the strains to levofloxacin, chloramphenicol, ceftazidime and trimethoprim/sulfamethoxazol (SXT) were evaluated via broth microdilution method according to the CLSI recommendations. Class 1 (intI-1), class 2 (intI-2), class 3 (intI-3) integron gene cassettes and integron 5'-3' conserved gene regions (intI-5'-3'CS) were investigated by polymerase chain reaction (PCR) using specific primers in all of the strains. Nucleotide sequence analysis of PCR products was performed in case of positive result, and the presence and size of plasmids were further investigated. The susceptibility rates of S.maltophilia strains to ceftazidime, chloramphenicol, SXT and levofloxacin were found as 24%, 66%, 93% and 95%, respectively, while MIC(50) and MIC(90) values were 64-128 µg/ml, 8-16 µg/ml, 1/19-2/38 µg/ml and 1-2 µg/ml, respectively. In PCR amplification with intI-1, intI-2 and intI-3 primers, 12%, 2% and 10% of the isolates yielded expectative bands, respectively. DNA sequence analysis of the amplified products revealed five isolates to harbour intI-1 gene, while intI class 2 and class 3 genes were not detected in any of the strains. Furthermore in PCR amplification with intI-5'CS and 3'CS primers, 20% of the strains yielded expected bands. Sequence analysis of these amplicons revealed the presence of quaternary ammonium compound resistance protein genes (qacL) in two, aminoglycoside adenyltransferase gene (aadA) in one and integron-associated recombination site (attI1) genes in five strains. Additionally, the presence of plasmids have been detected in 9 (9%) of the strains, however all of them was integron-negative. The sizes of plasmids were 2340, 1350, 2760, 18600, 20000, 3570-2540, 2510 and 5000-2540 base pairs, respectively. When the antibiotic susceptibility patterns of strains were compared with the presence of intI gene regions, no statistically significant relationship was observed (p> 0.05). In conclusion, the demonstration of integron class 1 genes and plasmids among clinical S.maltophilia strains is regarded as a warning data to indicate the potential for spread of those resistant strains in our hospital.

[NDM-1 cases and outbreaks in Turkey]. / Ülkemizdeki NDM-1 olgu ve salginlari

We are grateful to Hatipoglu and Turhan [Mikrobiyol Bul 2014; 48(1): 188-9] for their interest in our study published in Mikrobiyol Bul 2013; 47(2): 382-4. As Hatipoglu and Turhan mentioned in their comment, ertapenem is more sensitive than other carbapenem antibiotics for the identification of New Delhi Metallo-beta-lactamase (NDM-1) producers among carbapenem-resistant strains being studied. However, its low specificity [Dortet et al. Biomed Res Int 2014; 2014: 249856] makes it equal with other carbepenems. Since all the isolates in our study were not tested for ertapenem susceptibility, we used the susceptibility data for three carbapenems to increase the sensitivity of our study regarding isolate selection. We agree Hatipoglu and Turhan about the Modified Hodge Test (MHT) and we did not use MHT at all in our study. However we couldn't understand how they came to a conclusion that we used MHT and didn't mention in Material and Methods section. ZnSO4 supplemented MHT which was recommended by the authors [Dortet et al. Biomed Res Int 2014; 2014: 249856] has a sensitivity rate of about 85%. Thus we used molecular methods instead of MHT not to miss any single isolate. Hatipoglu and Turhan mentioned about previously reported four NDM-1 positive isolates without any international relation in Turkey. However, since this mentioned study [Alp et al. J Hosp Infect 2013; 84(2): 178-80] was published after the appeal, acceptance and publication of our study, eventually we didn't have the opportunity to discuss the data of Alp's report. In the same study authors stated that NDM-1 producing isolates were isolated from pediatric patients and had no connection with patients from Indian peninsula. At the same time Poirel et al. [Antimicrob Agents Chemother 2014; 58(5): 2929-33] reported in their study that NDM-1 producing isolates from pediatric patients had clonal relation with Enterobacter cloacae strains and subject to an outbreak. The evaluation of the previous reports about NDM-1 indicated that NDM-1 was initially originated from foreign sources before exhibiting endemicity in a country. Thus the situation in our region was not an exception. In conclusion, medical facilities taking care of foreign patients should pay particular attention to identification of NDM-1 isolates and establishment of appropriate control measures.

Fatal sepsis in a child with thalassemia major due to Serratia marcescens.

One of the most important causes of mortality in thalassemic patients is infectious disease. Thalassemic patients develop severe invasive infection caused by microorganisms that are rare in healthy individuals. We describe the case of a 13-year-old splenectomized boy who presented with septic shock and who died 36 h after admission, despite broad-spectrum antibiotics and aggressive supportive care. Serratia marcescens was isolated from cultures of blood and tracheal aspirate. It is known that rare microorganisms will cause severe community-acquired infection in splenectomized patients with thalassemia major.

[Isosporiasis in an elderly patient with chronic diseases: case report]. / Yasli Bir Hastada Kronik Hastaliklara Eslik Eden Isosporiyazis: Olgu Sunumu.

Isospora belli is a coccidian protozoon that can cause serious diarrhea especially in immunocompromised patients. The laboratory diagnosis depends primarily on the identification of oocysts in stool specimens by direct microscopic examination with iodine or special stains. This case is presented in order to draw attention to isosporiasis among the diarrheas that can be seen in elderly patients with several chronic diseases. A 81 year-old debilitated male, who had a history of hypertension, Alzheimer's disease, previous cerebrovascular accident and right hemiplegia, was admitted to our hospital complaining of malaise, anorexia, chills, abdominal pain, dysuria, cough, sputum and diarrhea of ten days duration. I. belli oocysts were detected by microscopic examination of the sample with iodine after concentration by formalin-ethyl acetate sedimentation. Then, modified acid-fast and trichrome stains were performed and I. belli oocysts were detected with both methods. Similar to this case, infections caused by I. belli can occur in elderly immunocompromised patients with several chronic diseases and inadequate nutrition and care. Consequently, in individuals with persistent diarrhea, examinations and tests should be carried out by taking their immune status into consideration and stool examinations should be done at frequent intervals using the concentrations methods and special stains.

Colistin use in pediatric intensive care unit for severe nosocomial infections: experience of an university hospital.

BACKGROUND: The aim of this study was to investigate the efficacy and safety of colistin therapy in pediatric patients with severe nosocomial infections in pediatric intensive care unit. METHODS: The medical records of patients treated with colistin at a 200-bed university children hospital were reviewed. RESULT: Thirty-one patients (male/female = 22/9; median age, 3 years; range, 3 months-17 years) received forty-one courses of colistin. The average dose of colistin was 4.9 ± 0.5 mg/kg/day and average treatment duration was 19.8 ± 10.3 days. Three patients who received concomitant nephrotoxic agent with colistin developed nephrotoxicity. Colistin treatment was well tolerated in other patients, and neurotoxicity was not seen in any patient. Favourable outcome was achieved in 28 (68.3%) episodes. Twelve patients died during the colistin therapy. Six of these patients died because of primary underlying disease. The infection-related mortality rate was found 14.6% in this study. CONCLUSION: In our study, colistin therapy was found to be acceptable treatment option for the severe pediatric nosocomial infections caused by multi-drug resistant bacteria. However, the use of concomitant nephrotoxic drugs with colistin must be avoided and renal function test should be closely monitored.

[Investigation of the presence of New Delhi metallo-beta-lactamase-1 (NDM-1) by PCR in carbapenem-resistant gram-negative isolates]. / Karbapeneme dirençli gram-negatif izolatlarda New Delhi metallo-beta-laktamaz-1 (NDM-1) varliginin PCR ile arastirilmasi

Bacteria producing New Delhi metallo-beta-lactamase-1 (NDM-1) exhibit high level resistance to beta-lactams including carbapenems. This broad-spectrum resistance limits treatment options for infections caused by NDM-1 producers. NDM-1 was first isolated from an Indian patient in Sweden; since then, NDM-1 producing isolates have been identified in many countries including Turkey. In this study, we investigated the presence of NDM-1 by PCR method in various gram-negative isolates recovered from clinical specimens in tertiary care hospitals in Samsun, Turkey. A total of 210 carbapenem-resistant gram-negative isolates (132 Acinetobacter baumannii, 54 Pseudomonas aeruginosa, 5 Pseudomonas putida, 8 Enterobacter cloacae, 3 Enterobacter aerogenes, 3 Klebsiella pneumoniae, 2 Providencia rettgeri, 2 Escherichia coli and 1 Citrobacter freundii) were included in the study. Identification and antibiotic susceptibility testing of the isolates were performed by using Vitek-2 Compact (bioMerieux, France) and BD Phoenix (BD Diagnostic Systems, MD) automated systems. The results of antibiotic susceptibility testing were interpreted according to the CLSI recommendations. In our study, NDM-1 gene was not detected in any of the clinical isolates by PCR. There was only one case study that reported the presence of NDM-1 in clinical isolates from Turkey [Poirel L et al. Antimicrob Agents Chemother 2012;56:2784]. Our data, together with the others, indicated that the existence of NDM-1 in clinical isolates is not common in Turkey. However, since NDM-1 is a plasmid-encoded enzyme, there is always a risk of spread of this resistance through the bacterial strains in our country. Therefore, continuous surveillance and investigation of carbapenem-resistant isolates with resistance patterns suggestive of NDM-1 may enable to identify NDM-1 producing isolates. Meanwhile special care should be given on rational antibiotic use and establishment of appropriate infection control policies to prevent the spread of NDM-1 producers and other potential resistant strains.

Comparison of Culture, Real-Time DNA Amplification Assay and Ehrlich-Ziehl-Neelsen for Detection of Mycobacterium tuberculosis.

OBJECTIVE: Mycobacterium tuberculosis is still a substantial health problem universally. Although culture is the gold standard method, reliable, rapid and new methods are required for effective struggle with disease. We retrospectively compared the results of Ehrlich-Ziehl-Neelsen (EZN) stain and real-time DNA amplification assay (BD ProbeTec ET system) with culture. STUDY DESIGN: Retrospective study. MATERIAL AND METHODS: A total of 703 samples, 182 pulmonary and 521 extra pulmonary, collected from 630 patients between May 2008 and February 2011 were evaluated. Culture was considered the gold standard. RESULTS: For pulmonary specimens, sensitivity, specificity, positive predictive and negative predictive values of BD ProbeTec ET and EZN were calculated to be 100%, 98.8%, 87.5%, 100% and 71.4%, 98.8%, 83.3%, 97.6%, respectively. For extra pulmonary specimens, sensitivity, specificity, positive predictive and negative predictive values of BD ProbeTec ET and EZN were calculated to be 80%, 98.7%, 76.9%, 98.9% and 24%, 98.3%, 42.8%, 96.2%, respectively. CONCLUSION: According to these results, we suggest that the BD ProbeTec ET system is more reliable than EZN. In addition, the BD ProbeTec ET system produces faster results. Based upon these results, we consider that the BD ProbeTec ET system may be employed in the diagnosis of M. tuberculosis.

Efficacy of tigecycline/colistin combination in a pneumonia model caused by extensively drug-resistant Acinetobacter baumannii.

Due to increasing drug resistance, available antimicrobial options are limited in the treatment of Acinetobacter baumannii infections. Particularly in cases caused by extensively drug-resistant (XDR) A. baumannii, combination regimens must also be taken into consideration. In this study, the efficacies of tigecycline, colistin and tigecycline/colistin combination on bacterial counts in lung tissue were investigated in a rat pneumonia model. One A. baumannii strain resistant to all antimicrobial agents except tigecycline and colistin was selected for the study. In vivo studies revealed a >3 log reduction in bacterial counts in the tigecycline, colistin and combination groups at 24 h and 48 h compared with the control group. No significant differences were determined between colistin, tigecycline and combination groups (P>0.05). On the other hand, differences between treatment groups and the control group were statistically significant (P=0.01). A greater reduction in bacterial counts was observed at 48 h compared with 24 h in the tigecycline group than in the colistin group (P=0.038 and P=0.139, respectively); the most significant decrease between 24 h and 48 h was observed in the combination group (P=0.014). Despite detection of in vitro synergistic activity in this study, no statistically significant differences were found between colistin, tigecycline and combination treatments in terms of efficacy on bacterial counts in lung tissue. In the treatment of infections with a high mortality rate such as pneumonia caused by XDR A. baumannii, combining tigecycline with colistin during the first 48 h and continuing treatment with one of these agents seems a rational approach.

Old agent, new experience: colistin use in the paediatric Intensive Care Unit--a multicentre study.

Nosocomial infections caused by multidrug-resistant (MDR) microorganisms are a common problem around the world, especially in Intensive Care Units. The aim of this study was to investigate the efficacy and safety of colistin therapy in paediatric patients with severe nosocomial infections caused by MDR Gram-negative bacteria. There were 87 episodes in 79 paediatric Intensive Care Unit patients in five different hospitals; each patient was treated intravenously with colistin and evaluated. Of the 79 patients, 54.4% were male and the median age was 30 months. The most commonly isolated microorganism was Acinetobacter baumannii, the most common isolation site was tracheal aspirate fluid and the most common type of infection was ventilator-associated pneumonia. The mean colistin dose in patients without renal failure was 5.4 ± 0.6 mg/kg/day, the mean therapy duration was 17.2 ± 8.4 days and the favourable outcome rate was 83.9%. Serious side effects were seen in four patient episodes (4.6%) during therapy; two patients suffered renal failure and the others had convulsive seizures. Other patients tolerated the drug well. The infection-related mortality rate was 11.5% and the probability of death within the first 9 days of treatment was 10 times higher than after the first 9 days. In conclusion, this study suggests that colistin is effective in the treatment of severe nosocomial infections caused by MDR Gram-negative bacteria and is generally well tolerated by patients, even after relatively long-term use.

Seroprevalence of Bordetella pertussis immunoglobulin G antibodies among children in Samsun, Turkey.

In this study, we aimed to investigate anti-pertussis immunoglobulin (Ig) G antibodies in the serum of children in our region vaccinated against pertussis with four doses. Between August 2008-2009, antibody levels to Bordetella pertussis (B. pertussis) antigens were studied in 385 serum samples from healthy children aged 1.5-18 years (y) vaccinated against pertussis in Samsun, Turkey. The study population was divided into six groups according to ages: 1.5-3 y; 4-5 y; 6-8 y; 10-12 y; 13-15 y; and 16-18 y. IgG antibodies to B. pertussis antigens were measured with a commercial ELISA kit. Mean age of the children was 9.6 +/- 5.3 y. Anti-pertussis IgG titers were positive in 48.3% of the cases. The lowest positivity rate was determined in the 4-5 y age group (28.1%) and the highest rate in the 16-18 y age group (64.2%). Geometric mean titer of anti-pertussis antibodies was 39.2 IU/ml, and again the lowest value was obtained in the 4-5 y age group (23.3 IU/ml) and the highest in the 16-18 y age group (51.4 IU/ml). The antibody levels to B. pertussis antigens significantly decrease 4-6 years after vaccination and again increase in school children, possibly due to natural infection.

Effect of 1-(1-Naphtylmethyl)-piperazine, an efflux pump inhibitor, on antimicrobial drug susceptibilities of clinical Acinetobacter baumannii isolates.

In this study, the effects of 1-(1-naphtylmethyl)-piperazine (NMP), an efflux pump inhibitor, on antimicrobial drug susceptibilities of 42 clinical Acinetobacter baumannii isolates were investigated by the disc diffusion method. The inhibition zone diameters of antibiotic discs were tested in the presence and absence of NMP and then these zone diameters were compared. Presence of NMP restored ciprofloxacin susceptibility in 15 intermediate and 2 resistant isolates. One ciprofloxacin resistant isolate became intermediate in the presence of NMP. One isolate resistant to gentamicin became intermediate with NMP. Interestingly, one isolate susceptible to meropenem became resistant in the presence of NMP. Although NMP increased the inhibition zone diameters of some of the tested antibiotics against the resistant isolates, the increase was not enough to restore susceptibility. In conclusion, the presence of NMP increases the zone diameters of ciprofloxacin and levofloxacin. Intermediate strains become susceptible but the resistant isolates do not.

[Investigation of the in vitro antibacterial effects of statins]. / Statinlerin in vitro antibakteriyel etkinliginin arastirilmasi.

It was previously shown that statins have anti-inflammatory, immunomodulatory and anti-oxidant effects. This study was aimed to investigate the in-vitro antibacterial effects of simvastatin and atorvastatin. In this study antibacterial activity of the statins were tested against 16 methicillin-susceptible Stophylococcus aureus (MSSA), 16 methicillin-resistant S.aureus (MRSA), 16 methicillin-resistant coagulase-negative Staphylococcus (MRCoNS), 9 vancomycin-susceptible Enterococcus faecium, 7 vancomycin-susceptible Enterococcus faecolis, 13 vancomycin-resistant E. faecium, 16 extended spectrum beta-lactamase (ESBL) positive Escherichia coli, 16 Pseudomonas aeruginosa, 16 Acinetobacter boumannii, 15 ESBL positive Klebsiella pneumoniae, 6 Stenotrophomonas maltophilio by broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) performance and interpretive guidelines. S. aureus ATCC 29213, S. aureus ATCC 25923, S. aureus ATCC 43300, Enterococcus faecalis ATCC 29212, K.pneumoniae ATCC 700603 and E. coli ATCC 35218 were tested as control strains. The results showed that minimum inhibitory concentration (MIC) values for all isolates were > 128 microg/ml for the two statins tested. However, MIC of simvastatin was 32 microg/ml for S. aureus ATCC 29213 and was 64 microg/ml for S. aureus ATCC 25923 and E. faecalis ATCC 29212 and was > 128 microg/ml for others, but MIC of atorvastatin was > 128 microg/mI for all standard strains. According to these results, we observed that simvastatin and atorvastain had no significant antibacterial effect in vitro. In this study, although no antibacterial effect of statins were determined in vitro, further studies are needed to investigate the combined effect of statins with antibacterial agents in the living organism.