scholarly journals Tetracycline resistance in Moraxella (Branhamella) catarrhalis: demonstration of two clonal outbreaks by using pulsed-field gel electrophoresis.

1991 ◽  
Vol 35 (11) ◽  
pp. 2453-2455 ◽  
Author(s):  
M C Roberts ◽  
Y J Pang ◽  
R C Spencer ◽  
T G Winstanley ◽  
B A Brown ◽  
...  
2003 ◽  
Vol 47 (9) ◽  
pp. 2844-2849 ◽  
Author(s):  
Eleonora Giovanetti ◽  
Andrea Brenciani ◽  
Remo Lupidi ◽  
Marilyn C. Roberts ◽  
Pietro E. Varaldo

ABSTRACT Sixty-three recent Italian clinical isolates of Streptococcus pyogenes resistant to both erythromycin (MICs ≥ 1 μg/ml) and tetracycline (MICs ≥ 8 μg/ml) were genotyped for macrolide and tetracycline resistance genes. We found 19 isolates carrying the mef(A) and the tet(O) genes; 25 isolates carrying the erm(A) and tet(O) genes; and 2 isolates carrying the erm(A), tet(M), and tet(O) genes. The resistance of all erm(A)-containing isolates was inducible, but the isolates could be divided into two groups on the basis of erythromycin MICs of either >128 or 1 to 4 μg/ml. The remaining 17 isolates included 15 isolates carrying the erm(B) gene and 2 isolates carrying both the erm(B) and the mef(A) genes, with all 17 carrying the tet(M) gene. Of these, 12 carried Tn916-Tn1545-like conjugative transposons. Conjugal transfer experiments demonstrated that the tet(O) gene moved with and without the erm(A) gene and with the mef(A) gene. These studies, together with the results of pulsed-field gel electrophoresis experiments and hybridization assays with DNA probes specific for the tet(O), erm(A), and mef(A) genes, suggested a linkage of tet(O) with either erm(A) or mef(A) in erythromycin- and tetracycline-resistant S. pyogenes isolates. By amplification and sequencing experiments, we detected the tet(O) gene ca. 5.5 kb upstream from the mef(A) gene. This is the first report demonstrating the presence of the tet(O) gene in S. pyogenes and showing that it may be linked with another gene and can be moved by conjugation from one chromosome to another.


2012 ◽  
Vol 75 (12) ◽  
pp. 2136-2141 ◽  
Author(s):  
LIZIANE S. da ROCHA ◽  
GAYATHRI U. GUNATHILAKA ◽  
YIFAN ZHANG

A total of 138 Listeria isolates from retail meat, including 58 Listeria welshimeri, 44 Listeria monocytogenes, and 36 Listeria innocua isolates, were characterized by antimicrobial susceptibility tests against nine antimicrobials. In addition, the 44 L. monocytogenes isolates were analyzed by serotype identification using PCR and genotyping using pulsed-field gel electrophoresis. Resistance to one or two antimicrobials was observed in 32 Listeria isolates (23.2%). No multidrug resistance was identified. Tetracycline resistance was the most common resistance phenotype and was identified in 22 Listeria isolates. A low prevalence of resistance to ciprofloxacin, erythromycin, gentamicin, and vancomycin was also detected. L. innocua isolates demonstrated the highest overall prevalence of antimicrobial resistance, 36.1%, followed by 34.1% in L. monocytogenes isolates and 6.9% in L. welshimeri isolates. Serotypes 1/2a, 1/2b, and 4b were identified in 19, 23, and 1 L. monocytogenes isolate, respectively. One isolate was untypeable. Fifteen L. monocytogenes isolates were antimicrobial resistant (12 were serotype 1/2b, 2 were 1/2a, and 1 was untypeable). A diverse population of L. monocytogenes isolates was identified, as evidenced by multiple pulsed-field gel electrophoresis patterns in the 44 isolates. The data indicate that Listeria contamination is common in retail meat. Although antimicrobial resistance still occurs at a low prevalence, multiple Listeria species can serve as reservoirs of antimicrobial resistance. Various antimicrobial susceptibilities may exist in L. monocytogenes isolates of different serotypes.


2005 ◽  
Vol 49 (3) ◽  
pp. 1198-1200 ◽  
Author(s):  
Sharon A. Crawford ◽  
Kristin R. Fiebelkorn ◽  
Jan E. Patterson ◽  
James H. Jorgensen

ABSTRACT Thirteen Neisseria meningitidis clinical isolates from Africa, Asia, and the United States for which the tetracycline MICs were elevated (≥8 μg/ml) were examined for 14 recognized resistance genes. Only the drug efflux mechanism encoded by tet(B) was detected. All isolates were in serogroup A, belonged to complex ST-5, and were closely related by pulsed-field gel electrophoresis analysis.


2021 ◽  
Vol 13 (3) ◽  
pp. 602-610
Author(s):  
Eugene Y. H. Yeung ◽  
Ivan Gorn

Pulsed-field gel electrophoresis (PFGE) has historically been considered the gold standard in fingerprinting bacterial strains in epidemiological studies and outbreak investigations; little is known regarding its use in individual clinical cases. The current study detailed two clinical cases in which PFGE helped to determine the source of their methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Patient A was found to have MRSA bacteremia after trauma in her pelvic area. MRSA was also found in her groin but not in her nostril and rectum. PFGE was performed that showed variable bands of her MRSA isolates from blood and groin, suggestive of different strains of MRSA. Her MRSA bacteremia was determined to be unrelated to her pelvic trauma. Patient B was found to have MRSA bacteremia after colonoscopy. MRSA was also found in his nostril and rectum. PFGE was performed that showed variable bands of his MRSA isolates from blood and rectum but identical bands of MRSA isolates from his blood and nostril. His MRSA bacteremia was determined to be unrelated to his colonoscopy procedure. The current study demonstrates the use of PFGE to rule out the source of bacteremia in individual clinical cases.


2005 ◽  
Vol 71 (7) ◽  
pp. 3674-3681 ◽  
Author(s):  
S. Thisted Lambertz ◽  
M.-L. Danielsson-Tham

ABSTRACT Approximately 550 to 600 yersiniosis patients are reported annually in Sweden. Although pigs are thought to be the main reservoir of food-borne pathogenic Yersinia enterocolitica, the role of pork meat as a vehicle for transmission to humans is still unclear. Pork meat collected from refrigerators and local shops frequented by yersiniosis patients (n = 48) were examined for the presence of pathogenic Yersinia spp. A combined culture and PCR method was used for detection, and a multiplex PCR was developed and evaluated as a tool for efficient identification of pathogenic food and patient isolates. The results obtained with the multiplex PCR were compared to phenotypic test results and confirmed by pulsed-field gel electrophoresis (PFGE). In all, 118 pork products (91 raw and 27 ready-to-eat) were collected. Pathogenic Yersinia spp. were detected by PCR in 10% (9 of 91) of the raw pork samples (loin of pork, fillet of pork, pork chop, ham, and minced meat) but in none of the ready-to-eat products. Isolates of Y. enterocolitica bioserotype 4/O:3 were recovered from six of the PCR-positive raw pork samples; all harbored the virulence plasmid. All isolates were recovered from food collected in shops and, thus, none were from the patients' home. When subjected to PFGE, the six isolates displayed four different NotI profiles. The same four NotI profiles were also present among isolates recovered from the yersiniosis patients. The application of a multiplex PCR was shown to be an efficient tool for identification of pathogenic Y. enterocolitica isolates in naturally contaminated raw pork.


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