Molecular characterization and antimicrobial susceptibility of methicillin-resistant staphylococcus aureus isolates from clinical samples and asymptomatic nasal carriers in Istanbul (Turkey)

Background

Methicillin-resistant Staphylococcus aureus (MRSA) has been a widespread problem in Turkish hospitals.

Aims

The aim of this study was to investigate the staphylococcal toxin genes of the clinical and nasal MRSA isolates, and their antibiotic resistance profiles.

Materials and Methods

Isolation of nasal and clinical bacteria was done following standard microbiological methods. The presence of antimicrobial resistance genes (mec A, pvl, tsst-1, and SEs genes) was determined using the real-time polymerase chain reaction (PCR) assay.

Results

Among nasal MRSA isolates, 66.7% were toxigenic. The distribution of genes was as follows: pvl 26.7%, tsst-1 3.3%, and SEs 36.7%. Therefore, the nasal MRSA isolates had a rate of 23.3% multidrug resistance (MDR) pattern to the non-beta-lactams antibiotics. All (100%) clinical MRSA isolates were found to be toxigenic. The distribution of genes was as follows; pvl 10%, tsst-1 6.7%, and SEs 100%. The clinical MRSA isolates had a rate of 60% MDR.

Conclusions

Following detection of pvl, tsst-1, and SEs among nasal and clinical MRSA isolates, and the presence of high antimicrobial resistance, the spread of these strains may be an additional factor contributing to the emergence of community-acquired (CA)-MRSA and hospital-acquired (HA)-MRSA. This study is the first to determine the resistance to linezolid and tigecycline in both nasal and clinical MRSA isolates, for the first time in Turkey. All nasal and clinical MRSA isolates were uniformly susceptible to vancomycin and quinupristin-dalfopristin. Our findings show that MRSA infections in Turkey can be empirically treated with vancomycin and quinupristin-dalfopristin based on the lack of demonstrable resistance to these drugs.

Should we leave the paper currency? A microbiological examination

Objetives

Pathogens can be transmitted to banknotes due to the personal unhygienic habits. The aim of study was to find the possible pathogens on the banknotes circulating in the market and also to present their antibacterial resistance and their various virulence factors using genotypic and phenotypic methods.

Material and methods

A total of 150 samples of banknotes were randomly collected between August 2017 and March 2018. VITEK systems were used for identification and antimicrobial susceptibility testing respectively. Antimicrobial resistance genes (mecA, van, extended-spectrum β-lactamase [ESBL] and carbapenemases) and staphyloccoccal virulence genes (staphyloccoccal enterotoxins [SEs], pvl, and tsst-1) were determined using with real-time PCR.

Results

Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Enterococcus spp., Gram-negative enteric bacteria, non-fermentative Gram-negative bacteria and Candida spp. were detected 48%, 54.7%, 56%, 21.3%, 18.7%, and 4%, respectively. Methicillin-resistant S. aureus, vancomycin-resistant enterococci and ESBL producing Gram-negative were found 46.8%, 1.3%, and 28.7%, respectively. Pvl, tsst-1, and SEs genes were found in a 2.8/4.9%, 1.4/1.2%, and 100/ 87.8% of the S. aureus/CoNS strains, respectively. The sea gene was found the most common enterotoxigenic gene. bla_TEM, bla_SHV, blaCTX-M-2, blaCTX-M-1, bla_KPC, and blaOXA-48 were found 55.8%, 46.5%, 41.2%, 18.6%, 18.6%, and 18.6%, respectively in Gram-negative strains.

Conclusion

These results is very important to highlight hygienic status of paper currencies. This can be considered as an indication that banknotes may contribute to the spread of pathogens and antimicrobial resistance. Therefore, we may need to start using alternative products instead of banknotes.

Investigation of zoonotic infections in risk groups in Ordu University Hospital, Turkey

AIMS

Zoonotic diseases, which are a major public health problem in our city, have a negative impact on public health and also cause economic losses due to yield losses of animals and deaths. This study was carried out to determine the seroprevalence of tularemia, bartonellosis, brucellosis, Q fever, and cystic echinococcosis in the risk groups for zoonotic infection.

SUBJECTS AND METHODS

Ninety serum samples were taken from people in the risk groups in covering veterinarian, butchers, farmers and examined with the following tests: Microagglutination test for tularemia, indirect fluorescent antibody test (IFAT) for bartonellosis, standard tube agglutination test for brucellosis, IFAT IgG for Q fever, and enzyme-linked immunosorbent assay IgG test for cystic hydatid.

STATISTICAL ANALYSIS USED

The Chi-square analysis was used to assess, and the logistic regression analysis was used to identify the risk factors.

RESULTS

The analyzed all serum samples were found to be seronegative for tularemia, bartonellosis, and hydatid cyst antibodies. When analyzed for Coxiella burnetii with IgG antibody titers, it was determined that 23 samples (25.6%) were seropositivity. When brucellosis was analyzed with serological tests for Brucella, it was positive in seven samples (7.8%).

CONCLUSIONS

In this study, examined in the risk groups in which it is located along black sea coast of Turkey for tularemia, bartonellosis, and hydatid cysts, seropositivity was not found. When Brucella was tested, 7.8% was found to be positive, and when analyzed in terms of Q fever, 25.6% of people were determined to be seropositive. In conclusion, in our region, Q fever seropositivity was found to be higher in the risk groups. Therefore, most of the zoonotic disease look like not so common in the region, out of tularemia.

[Short communication: Determination of methicillin resistance in staphylococci with different methods and detection of multiple antibiotic resistance]

The aims of this study were to determine the methicillin resistance of a total of 256 staphylococcus strains [213 Staphylococcus aureus and 43 coagulase negative staphylococci (CNS)], isolated from different clinical samples and hospital environmental specimens by different methods and to detect multiple antibiotic resistance in these isolates. Methicillin resistance of staphylococci was investigated by using oxacillin agar screening (OAS), oxacillin disk diffusion (ODD), cefoxitin disk diffusion (CDD), PBP2a latex agglutination (LA) and microdilution tests. The resistance of the strains against penicillin G, amoxycillin/clavulanate, cephalothin, tetracycline, erythromycin, fusidic asid, ofloxacin, vancomycin, co-trimoxazole and gentamicin was investigated by standard disk diffusion method. As a result, 152 (71.3%) S. aureus and 30 (69.7%) CNS isolates were found to be methicillin-resistant with the use of OAS and PBP2a LA tests, respectively. The numbers of the isolates which were detected as methicillin-resistant and methicillin-susceptible were 182 and 74 by OAS; 183 and 73 by ODD; 181 and 75 by SDD; 180 and 76 by PBP2a LA; 183 and 73 by microdilution tests, respectively. There was no statistically significant differences-between the results obtained by all of the methods (p > 0.05), however the sensitivity of PBP2a LA test was lower in the detection of methicillin resistance in S. aureus strains. CDD test which was found to be as sensitive as ODD test, may be preferred in the detection of methicillin resistance in staphylococci. In our study staphylococci which were sensitive to methicillin, were also found generally sensitive to the other antibiotics, whereas staphylococci which were resistant to methicillin were also resistant to the other antibiotics. The difference between methicillin sensitive and resistant staphylococci in terms of the rates of resistance against other antibiotics was found statistically significant with the exception of fusidic acid (p < 0.05). The resistance rates of isolates for fusidic acid were very low and all of the strains were susceptible to vancomycin. In conclusion, for better determination of methicillin resistance, agar screening test which is proposed as a confirmatory test by CLSI, should be used when necessary.

[Investigation of hemodialysis patients in terms of the presence of occult hepatitis B]

The presence of hepatitis B virus (HBV) DNA in case of negative HBV surface antigen (HBsAg) in serum is known as "occult hepatitis B". There are many reports indicating that occult HBV infections are more frequently encountered in case of hepatocellular carcinoma, hemodialysis practice and co-infections with hepatitis C virus (HCV). The aim of this study was to investigate the presence of HBV-DNA in HBsAg negative hemodialysis. patients and subjects who had never experienced hemodialysis. A total of 226 HBsAg negative sera were included to the study, of which 153 were from hemodialysis patients (97 male, 56 female; mean age: 41.3 +/- 5.8 years), and 73 were from non-hemodialyzed individuals (46 male, 27 female; mean age: 36.5 +/- 6.9 years) who had serological evidence of previous HBV and HCV infections. Of these 73 subjects, 41 were anti-HCV positive, 22 were "anti-HBc IgG positive alone", seven were anti-HBc IgG and anti-HBs positive, and three were anti-HBc IgG and anti-HBe positive, while 40 of 153 (26.1%) hemodialysis patients were anti-HCV positive. HBV and HCV markers were detected by commercial enzyme immunoassays (bioMerieux, France and Murex, UK, respectively), and HBV-DNA testing was performed by a commercial real-time polymerase chain reaction (PCR; 5700 and 7700 Sequence Detection System, Applied Biosystems, UK) assay. Nineteen (12.4%) of HBsAg-negative hemodialysis patients and five (6.8%) of the non-hemodialyzed subjects were found positive for HBV-DNA (viral loads were > or =10(4) copies/ml, and 10(3)-10(4) copies/ml, repectively). The rates of occult HBV infection in the anti-HCV positive hemodialysis patients and anti-HCV positive non-hemodialyzed subjects were detected as 27.5% (11/40) and 2.4% (1/41), respectively. These rates in the other groups were found as follows; 7.1% (8/113) in the anti-HCV negative hemodialysis patients, 9.1% (2/22) in the "anti-HBc positive alone" subjects, and 20% (2/10) in the subjects positive for anti-HBc+anti-HBs or anti-HBe. The results of this study indicated that the prevalence of HBV viremia (12.4%) in hemodialysis patients being more prominent in those of anti-HCV positive patients (27.5%) should not be overlooked. In conclusion, the hemodialysis patients should be screened by sensitive PCR-based methods for occult HBV infections, even if they were negative for HBsAg, in order to prevent or at least to decrease the transmission risk of HBV infection which is still an important health problem in dialysis units.

[Investigation of the presence of Clostridium difficile in antibiotic associated diarrhea patients by culture and toxin detection methods]

Clostridium difficile-associated disease can be observed especially in hospitalized patients who use broad-spectrum antibiotics. The aim of this study was to investigate the presence of C. difficile as the causative agent of diarrhea in outpatients and inpatients. During January-December 2005, 45 outpatients and 46 inpatients (of them 11 were intensive care unit patients) who had developed diarrhea due to antibiotic use, were included to the study. In addition 7 intensive care unit personnel and 20 food handlers were also included to the study in order to detect their carrier states. The age range of patients was 16-80 years, and of them 45 (49.5%) were male, while the age range of the personnel was 25-55 years, and of them 21 (78%) were male. Stool samples collected from the study groups were cultivated in C. difficile agar media (C. difficile Agar Base, Oxoid) as well as on routine bacteriologic media, and C. difficile growth was confirmed by latex agglutination test with the use of specific antisera. The presence of C. difficile toxin A was investigated by latex method (Oxoid, UK), and toxin A and B was searched by enzyme-linked immunoassay (ELISA; Seramun GmbH, Serazym C. difficile Toxin A+B), in the stool samples. While C. difficile was isolated from 13 (14.3%) of the 91 samples, no positive result was detected in the personnel. There was no statistically significant difference between outpatient and inpatient groups by means of C. difficile culture positivity (15.5% and 17.1%, respectively) (p>0.05). All of the culture positive samples were also found positive by ELISA Toxin A+B method (100%), but only 4 of them (30.7%) yielded positive result by Toxin A latex test. It was detected that 84.6% (11/13) of the patients had used ampicillin/sulbactam, 7.7% (1/13) used cotrimoxazole-SXT, and 7.7% (1/13) used macrolide antibiotics. The use of ampicillin/sulbactam was found statistically significant in development of diarrhea (p<0.05). Our data indicated that ELISA Toxin A+B is a reliable method with 100% specificity and sensitivity in the rapid diagnosis of C. difficile until the culture results were obtained, however, although specificity of Toxin A latex test is 100%, its use alone as a primary rapid diagnostic test was not recommended because of its low (30.7%) sensitivity.

Effect of topical dexamethasone and ciprofloxacin on bacterial flora of healthy conjunctiva

PURPOSE

To investigate the effects of topical dexamethasone and ciprofloxacin, alone and in combination, on the colony counts of conjunctival bacterial flora of healthy subjects.

METHODS

A total of 100 healthy subjects were randomly divided into four groups, consisting of 25 subjects each. Group 1 was treated with dexamethasone phosphate 0.1% (Maxidex). Group 2 was treated with ciprofloxacin 0.3% (Ciloxan) and Group 3 with a combination of these drugs. Group 4 received artificial tear solution (Tears Naturale) and served as control. The drops were administered one drop every 1 min. A pretreatment culture and recultures at 30, 90, and 180 min after application of final drops were performed on all subjects. The bacterial growth was evaluated in a quantitative manner. All cultures were performed in a double-masked fashion. ANOVA test was used for statistical analyses.

RESULTS

While there was no significant difference among mean number of pretreatment colonies between the groups (P=0.85); the differences at 30, 90, and 180 min were statistically significant (P<0.001). During the study there was no statistically significant change in colony counts in Groups 1 and 4 (P=0.66 and 0.55, respectively). The colony count numbers decreased significantly at 30 and 90 min in Group 2 (P<0.001 and P=0.004) and at 30 min in Group 3 (P=0.002).

CONCLUSION

Topically applied dexamethasone did not cause a significant change in colony counts of the healthy conjunctiva. Both ciprofloxacin and a combination of ciprofloxacin and dexamethasone were effective in the reduction of bacterial ocular flora.

[Isolation frequency of Burkholderia cepacia from cystic fibrosis patients]

Microorganisms such as Pseudomonas aeruginosa, Staphylococcus aureus and Haemophilus influenzae frequently cause colonization and infection in airways of patients with cystic fibrosis. Burkholderia cepacia has also been isolated in patients with cystic fibrosis since 1980. In this study, we aimed to determine the colonization rate of B. cepacia in 286 sputum samples obtained from 129 cystic fibrosis patients. Selective media for B. cepacia were used besides the routine microbiological media in order to increase the isolation rate. The colonies were identified by biochemical tests and the antibiotic susceptibilities of the strains were determined by disc diffusion method. Pathogenic bacteria (S. aureus, P. aeruginosa, Enterobacteriaceae, Streptococcus pneumoniae, H. influenzae) were isolated in 52 of 129 patients (40%) and 66 of 286 sputum samples (23%). In addition 2 B. cepacia strains were isolated from two different patients (1.55%). B. cepacia is now being considered as a pathogen isolated from sputum samples of patients with cystic fibrosis with an increasing frequency and causing severe clinical features. According to these results it can be concluded that, the use of selective media for B. cepacia isolation, should be taken into consideration especially by the clinical microbiology laboratories collaborating with the cystic fibrosis centers.

A quantitative study of genital skin flora and urinary colonization in spinal cord injured patients

This study was performed to define the relation between colonization of genital skin flora and bacteriuria in spinal cord injured patients with neurogenic bladder dysfunction. Twenty-seven female and 23 male spinal cord injured patients were included in the study. Patients were evaluated regarding their type of bladder management, educational status, level and degree of the spinal cord lesion. Quantitative cultures were obtained from the perineum labium/dorsum of penis, external meatus of urethra, and urine. We investigated whether the organisms isolated from urine were also present in one or more skin sites in every patient. In total 54 identical bacterial isolates were observed both from urine and one or more skin sites in 43 of the patients. Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae, and Proteus stuartii were the most common bacterial isolates. The distribution of identical colonization of genital skin flora with urine were as follows: 30 in urethra, one in perineum, four in urethra and perineum, nine in urethra and labium/dorsum of penis, and 10 in both three skin sites. Identical colonization of both perineum and labium/dorsum of penis with urine were significantly higher in female patients than those of males (P = 0.037, P = 0.003, respectively). No significant difference was found in the presence/distribution of colonization with respect to type of bladder management, educational status, and neurologic status. These results demonstrate the importance of the urethra, perineum, and labium/dorsum of penis as a source of bacteria causing urinary infection in spinal cord injured patients.