Role of wild birds as carriers of multi-drug resistant Escherichia coli and Escherichia vulneris

Emergence and distribution of multi-drug resistant (MDR) bacteria in environments pose a risk to human and animal health. A total of 82 isolates of Escherichia spp. were recovered from cloacal swabs of migrating and non-migrating wild birds. All bacterial isolates were identified and characterized morphologically and biochemically. 72% and 50% of isolates recovered from non-migrating and migrating birds, respectively, showed positive congo red dye binding (a virulence factor). Also, hemolysin production (a virulence factor) was showed in 8% of isolates recovered from non-migrating birds and 75% of isolates recovered from migrating birds. All isolates recovered from non-migrating birds were found resistant to Oxacillin while all isolates recovered from migrating birds demonstrated resistance to Oxacillin, Chloramphenicol, Oxytetracycline and Lincomycin. Some bacterial isolates recovered from non-migrating birds and migrating birds exhibited MDR phenotype. The MDR isolates were further characterized by API 20E and 16S rRNA as E. coli and E. vulneris. MDR Escherichia isolates contain ~1-5 plasmids of high-molecular weights. Accordingly, wild birds could create a potential threat to human and animal health by transmitting MDR bacteria to water streams and other environmental sources through their faecal residues, and to remote regions by migration.

Drug resistance profiles and clonality of sporadic Shigella sonnei isolates in Ankara, Turkey

The aims of this study were to investigate drug resistance rates, types of extended spectrum beta lactamases (ESBLs), and molecular epidemiological characteristics of 43 Shigella sonnei isolates. Ampicillin-sulbactam, amoxicillin-clavulanate, chloramphenicol, and ciprofloxacin were the most active antibiotics. Five isolates harbored blaSHV-12, blaTEM-1 and blaCTX-M-15. More than 90% of the isolates had an indistinguishable pulsotype.

Detection & characterization of necrotoxin producing Escherichia coli (NTEC) from patients with urinary tract infection (UTI).

Background & objectives: Urinary tract infections (UTI) are a serious health problem affecting millions of people each year. Although appreciable work on various aspects of UTI including aetiology per se has been done, information on the emerging pathogens like necrotoxigenic Escherichia coli (NTEC) is largely lacking in India. In the present study E. coli isolates from patients with urinary tract infection from northeastern India were investigated for detection and characterization of NTEC. Methods: E. coli isolated and identified from urine samples of patients with UTI were serotyped. Antibiogram was determined by disc diffusion test. Plasmid profile was also determined. Virulence genes of NTEC (cnf1, cnf2, pap, aer, sfa, hly, afa) were detected by PCR assay. E.coli isolates carrying cnf gene (s) were identified as NTEC. Results: A total of 550 E. coli were isolated and tested for the presence of cnf genes. Of these, 84 (15.27%) belonged to NTEC. The cnf1 gene was present in 52 (61.9%) isolates, cnf2 in 23 (27.4%) and 9 (10.7%) carried both cnf1 and cnf2 genes. All the NTEC strains were found to harbour the pap and aer genes. Serogroup O4 was found to be the most common among the 12 serogroups identified amongst the NTEC isolates. Majority of the isolates (96.4%) were sensitive to furazolidone and were highly resistant to ampicillin. NTEC were found to harbour different numbers of plasmids (1 to 7). No association was observed between the number of plasmids and the antibiotic resistance of the isolates. Interpretation & conclusions: The results of the present study showed that about 15 per cent of E. coli isolates associated with UTI belonged to NTEC. More studies need to be done from other parts of the country.

Plasmid Profile of Uropathogens among Children.

Aims: The study was carried out in order to determine the plasmid profile, antibiotic susceptibility pattern and the type of antimicrobial resistance (whether it is chromosomal or plasmid mediated) among producers of extended spectrum beta-lactamases of uropathogens in children. Study Design: A cross-sectional study of three hundred children in a hospital. Place and Duration of Study: Department of Pediatrics (Pediatrics Ward) and Department of Medical Microbiology and Parasitology, Nnamdi Azikiwe University Teaching Hospital, Nigeria between January 2009 to September 2010. Methodology: Clean-catch urine samples were collected from 300 children aged 1 month to 16 years with suspected community acquired urinary tract infection. Isolated bacteria were identified using standard microbiological techniques. Antimicrobial susceptibility test was carried out by disc diffusion method. Extended Spectrum Beta- Lactamase (ESBL) was determined among the Gram-negative bacteria using double disc synergy test (DDST). The plasmid DNA of the bacterial isolates was extracted using alkalysis method and electrophoresed on 0.8% agarose gel stained with 2μl ethidium bromide (EtBr). Result: The result of the study showed that Staphylococcus aureus had the highest prevalence among gram positive bacteria. Escherichia coli had the highest prevalence among gram negative bacteria. Staphylococcus aureus showed cross resistance towards some of the antimicrobial agents. Escherichia coli and Pseudomonas showed multiple drug resistance. All the uropathogens isolated were 100% susceptible to imipenem. The study highlights among the ESBL-producers, plasmids of higher molecular weight of 30Kb. Conclusion: It is therefore suggested that appropriate antimicrobial agent be administered to reduce the risk of multi-drug resistance and avert the ineffectiveness of antimicrobial agents.

Determination of microbial quality and plasmid-mediated multidrug resistant bacteria in fountain drinking water sources in Turkey.

The bacterial contamination as the total aerobic bacteria, coliform and fecal coliform numbers were determined and analyzed for temperature, pH, conductivity and dissolved oxygen in seasonally collected water samples from fifteen different stations placed in Adana- Tufanbeyli road line during March 2008- January 2009. In addition, antibiotic resistance profiles of isolates were examined against frequently used antibiotics, and analyzed plasmid DNA of multiple antibiotic resistant (MAR) isolates. Total aerobic bacteria in fountain water samples was determined as 3x103 CFU ml-1 and total and fecal coliforms were determined 460 MPN/100 ml. Results obtained from biochemical analysis showed that 121 of the isolates were Proteus vulgaris, 69 Escherichia coli, 51 Pseudomonas aeruginosa and 28 Citrobacter spp. According to these results, the existence of Vibrio parahaemolyticus in stations 2 and 10, and Streptococcus faecalis in stations 11 and 15 respectively were confirmed. Clostridium perfringens was not detected in water samples. A total of 273 isolates were tested for antimicrobial susceptibility by agar disc diffusion methods. A total of sixteen antibiotics were used for determination of antibiotic resistance of isolates. Resistance to bacitracin, vancomycine, cephalothin and ampicillin was detected in 77, 77, 63 and 50%, respectively. Multiple antibiotic resistance (MAR) value > 0.25 was determined in 68.4% of identified 273 isolates and meaning of this percentage were resistant to four and more antibiotics. Plasmid DNA was isolated from 22 isolates with multiple antibiotic resistance index ranged from 0.3 to 0.6 taken randomly by agarose-gel electrophoresis, some of them contain a high-molecular weight plasmid DNA. Highlight of our study that the appearance of potential antibiotic resistances in fountain drinking water requires increased surveillance for risk assessment and prevention strategies to protect public health.

Biochemical properties, enterohaemolysin production and plasmid carriage of Shiga toxin-producing Escherichia coli strains

Thirty-eight strains of Shiga toxin-producing Escherichia coli (STEC) were characterised in terms of biochemical properties, enterohaemolysin production and plasmid carriage. A wide variation in the biochemical properties was observed among the STEC, with 14 distinct biotypes identified. Biotype 1 was the most common, found in 29 percent of the strains. Enterohaemolysin production was detected in 29 percent of the strains. Most of the bacterial strains (95 percent) carried one or more plasmids and considerable heterogeneity in size and combinations was observed. Seven distinct plasmid profiles were identified. The most common profile, characterised by the presence of a single plasmid of ~90 kb, was found in 50 percent of these strains. These data indicate extensive diversity among STEC strains. No correlation was found among biotype, serotype, enterohaemolysin production and plasmid profile.

Plasmid profiling of Flavobacterium psychrophilum isolates from ayu (Plecoglossus altivelis altivelis) and other fish species in Japan

In order to evaluate the genetic variability of the causative agent of cold water disease (CWD), plasmid profiling was used to characterize Flavobacterium (F.) psychrophilum isolates (n = 169). Size analysis of plasmids in F. psychrophilum isolates (n = 128) from several fish species demonstrated that six kinds of plasmids were harbored, and ayu isolates had different profiles compared to other isolates. Moreover, multiple isolates (n = 41) from CWD outbreaks in 2002 to 2003 at a single ayu farm were examined to determine differences between isolates from successive outbreaks and showed different profiles by the sources of seedlings.

Homology of Carbapenem-resistant Klebsiella pneumoniae / 中华医院感染学杂志

OBJECTIVE To analyze the homology of carbapenem-resistant Klebsiella pneumoniae(KPN),offering help for clinical therapy and nosocomial infection control.METHODS The antimicrobial-resistant phenotype of forty carbapenem-resistant K.pneumoniae strains was analyzed by the WHONET 5.4 soft and the resistant genotypes were determined by plasmid profile analysis and pulse-field gel electrophoresis(PFGE).RESULTS Analyzing antimicrobial-resistant phenotype to usual eighteen clinical drugs,the main drug resistant profiles were pan-resistant and only sensitive to tobramycin among the eight antimicrobial-resistant profiles(72.5%).Additionally,the main strains were type Ⅰ and type Ⅱ among the five strains analyzed by plasmid profile(82.5%).When analyzed by PFGE,five types were identified and among these strains type Ⅰ was predominant in 34 strains(85.0%).CONCLUSIONS The strains used in this study exhibit higher homology.Therefore,clinical departments and nosocomial infection departments should pay more attention to these strains to avoid outbreak.

Antibiotic Resistance and Genetic Analysis of Shigella sonnei Strains Isolated in South Korea and Japan

A total of 35 strains of Shigella sonnei, 21 strains isolated in South Korea from 2000 to 2001 and 14 strains isolated in Japan from 2001 and 2002 were analyzed for antimicrobial susceptibility, plasmid profile and molecular epidemiology. Using polymerase chain reaction (PCR) method, the strains were tested for the presence of virulence genes. And then reversed passive latex agglutination(RPLA) test was used to determine if the strain was Shiga-toxin producing. Their random amplified polymorphic DNA (RAPD) patterns were examined. Pulsed-field gel electrophoresis (PFGE) patterns were also analyzed. Most strains showed multiple resistance to more than four antimicrobial agents, i.e., tetracycline, erythromycin, streptomycin and vancomycin. All South Korea strains were susceptible to chloramphenicol and gentamicin, while all Japan strains were susceptible to kanamycin and cefoperazone. The antibiogram could be classified into 6 groups. By PCR, ipaH gene was detected from all strains, but set1A and set1B genes were not. Sen and ial genes were detected from 19 strains (54.3 %). Especially, stx gene was positive in 11 of the 35 strains by PCR method but not confirmed by RPLA method. The strains were differentiated into 12 groups by plasmid profile and 6 arbitrary groups (a to f) by RAPD analysis. The isolates could be grouped into 5 (A to E) PFGE patterns including 3 subgroups A-1, A-2 and A-3. Type A was the major type (82.9 %).

Characteristics of Shigella sonnei Isolated in Kyungsangbuk-do in 1998: Biochemical Characteristics, Biotyping, Antibiotic Resistance Pattern, and Plasmid Profile / 한국역학회지

Thirty nine strains and 109 strains of Shigella sonnei were isolated from the outbreaks of Youngchun and Kyungju, respectively, while 15 strains were isolated from sporadic cases of eight regions in Kyungbuk province from September to November in 1998. We investigated the relationship among the S. sonnei strains by using biochemical characteristics, biotyping, antibiotic resistance pattern, and plasmid profile. Among the isolates, seven strains of S. sonnei isolated in Youngchun showed gelatin hydrolyase positive but the others showed gelatin hydrolyase negative. One hundred and fifty two strains were a type, while eleven among thirty nine strains isolated in Youngchun were g type. Antibiotics resistance patterns of S. sonnei strains isolated in Youngchun and Kyungju were significantly different. Thirty nine strains of S. sonnei isolated in Youngchun were resistant to SM, TE, and TMP/SMX, while eighty six of S. sonnei among one hundred and nine strains isolated in Kyungju were resistant to AM, CB, K, SM, TE, and TMP/SMX. Antibiotics resistance patterns of residual twenty three isolates were similar to those of eighty six strains. The Plasmid profiles of strains of S. sonnei isolated from the Kyungju were different from those of S. sonnei strains isolated in Youngchun. The Plasmid profiles of S. sonnei strains isolated from Youngchun were identical to those of a S. sonnei strains randomly selected from the outbreak in Daegu in 1998. The Plasmid profiles of S. sonnei strains isolated from Kyungju were identical to those of two strains of S. sonnei randomly selected from the outbreaks of Kanglung and Wonju in 1998. From the above results, it is considered that the strains of S. sonnei isolated from Kyungju and Youngchun region are not identical clone.

Epidemiological Studies of Yersinia pseudotuberculosis Infection by Plasmid DNA Profile Assay / 감염

BACKGROUND: In order to investigate transmission route of Yersinia pseudotuberculosis infection in Korea, we tried epidemiological study among human strains, mountain spring water strain and wild mouse strain which were isolated in north eastern area of Seoul on spring in 1996. METHODS: Plasmid profile (Restriction Endonuclease Analysis of Virulence Plasmid DNA analysis: REAP) assay in addition to serotyping were performed among human strains, mountain spring water strain and wild mouse strains. RESULTS: All isolates were the same O serotype of 4b and the same REAP pattern of type D. CONCLUSION: These results suggested that wild mice (especially Apodemus agrarius) were one of main reservoir of Y. pseudotuberculosis in Korea and their fecal material might contaminate mountain spring water. Most of human infections of Y. pseudotuberculosis were originated from drinking of contaminated mountain spring waters in Korea.

Nosocomial Outbreak of Methicillin-resistant Staphylococcus aureus Analyzed by Molecular Epidemiology / 병원감염관리

BACKGROUND: An outbreak of nosocomial infection due to methicillin-resistant Staphylococcus aureus (MRSA) was suspected at Seoul National University Hospital because the isolation rate of MRSA from patients with surgical wounds or other exudates was increased in one month period. To demonstrate the clonality of these isolates, restriction endonuclease analysis of plasmid DNA (REAP) and pulsed-field gel electrophoresis (PFGE) were performed. METHODS: Among the MRSA isolates in one month period, seventeen MRSA isolates from eleven surgical wound specimens and six other specimens were tested, Six isolates were taken from two patients at various times during hospitalization, Plasmid DNA was isolated by a modification of the alkaline lysis method and digested by EcoRI, The restriction analysis of SmaI-digested chromosomal DNA of MRSA strains was done by PFGE. RESULTS: Two representative groups were identified among fourteen isolates from ten patients. PFGE analysis showed seven isolates from five patients were of the same group, but REAP showed a different pattern on one isolate. Other seven isolates from five patients were classified as the another same group by PFGE, and they could be divided into five groups by REAP. And the remainders showed different PFGE patterns each other. CONCLUSIONS: The outbreak strains of this study could be divided into two different groups by PFGE and REAP. Furthermore, one group of the outbreak-related isolates showed entirely identical pattern. by both PFGE and REAP. The combination of more than one molecular epidemiological technique should be performed in order to demonstrate the clonality of the outbreak strains.

Nosocomial Outbreak of Methicillin-resistant Staphylococcus aureus Analyzed by Molecular Epidemiology / 병원감염관리

BACKGROUND: An outbreak of nosocomial infection due to methicillin-resistant Staphylococcus aureus (MRSA) was suspected at Seoul National University Hospital because the isolation rate of MRSA from patients with surgical wounds or other exudates was increased in one month period. To demonstrate the clonality of these isolates, restriction endonuclease analysis of plasmid DNA (REAP) and pulsed-field gel electrophoresis (PFGE) were performed. METHODS: Among the MRSA isolates in one month period, seventeen MRSA isolates from eleven surgical wound specimens and six other specimens were tested, Six isolates were taken from two patients at various times during hospitalization, Plasmid DNA was isolated by a modification of the alkaline lysis method and digested by EcoRI, The restriction analysis of SmaI-digested chromosomal DNA of MRSA strains was done by PFGE. RESULTS: Two representative groups were identified among fourteen isolates from ten patients. PFGE analysis showed seven isolates from five patients were of the same group, but REAP showed a different pattern on one isolate. Other seven isolates from five patients were classified as the another same group by PFGE, and they could be divided into five groups by REAP. And the remainders showed different PFGE patterns each other. CONCLUSIONS: The outbreak strains of this study could be divided into two different groups by PFGE and REAP. Furthermore, one group of the outbreak-related isolates showed entirely identical pattern. by both PFGE and REAP. The combination of more than one molecular epidemiological technique should be performed in order to demonstrate the clonality of the outbreak strains.

Antimicrobial drug resistance and molecular charaterization of R-plasmid of escherichia coli isolated from urine / 대한비뇨기과학회지

Ninety nine strains of Escherichia coli isolated from clinical urine specimens in Taegu area were tested for the antimicrobial susceptibility to 20 drugs and studies for molecular and genetic characterization of R-plasmid. All strains were susceptible to amikacin (Ak), moxalactam(Mx), norfloxacin(Nf), ciprofloxacin(Cf) and ofloxacin(Of). One-6.1% of the strains were resistant to tobramycin(To). nalidixic acid(Na), enoxacin(Ex), pefloxacin(Pf) and rifampin(Rf), 17.2-31.3% to gentamicin(Gm), cephalothin(Ct) and cephamandole(Cfm), and 59.6-84.4% to kanamycin (Km), streptomycin(Sm), a.mpicillin(Ap), chloramphenicol(Cm), tetracycline(Tc), sulfisomidine (Su) and trimethoprime(Tp). MIC90 of Ak, Mx, Ex, Nf, Cf, Of and Pf were below the aritimicrobial concentration tested. In multiple drug resistance patterns, resistance to 7 drugs (CmTcSmSuAp TpKm) were most frequently encountered. Except Na and Rf in 66.4 % of resistant strains, most or drug resistance were co-transferred to recipient E.coli RG488 or RG176, indicating that multiple drug resistance was R-plasmid mediated phenomenon. Plasmid profiles for molecular characterization of R-plasmids from B. coli strains were studied through the methods of alkaline SDS lysis and agarose gel electrophoresis. R-plasmids were 40.9-122.3 mega dalton in molecular size. Pst I restriction enzyme digestion patterns of R-plasmid DNAs were examined. R-plasmids with different molecular weights and phenotype markers showed different restriction patterns. pDE9l58 and pDE 9055, which have same molecular weight and phenotype marker except Cfm, showed identical restriction pattern.