scholarly journals Deceiving Phenotypic Susceptibility Results on a Klebsiella pneumoniae Blood Isolate Carrying Plasmid-Mediated AmpC Gene blaDHA-1

2021 ◽  
Vol 11 ◽  
Author(s):  
Susan Realegeno ◽  
Kevin Ward ◽  
Omai B. Garner ◽  
Shangxin Yang
Keyword(s):  
Blood Culture ◽  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
The United States ◽  
Resistance Mechanisms ◽  
Phenotypic Characterization ◽  
High Morbidity ◽  
Beta Lactam ◽  
Blood Isolate ◽  
Resistance Patterns

Carbapenem-resistant Klebsiella pneumoniae (CRKP) frequently causes hospital-acquired infections and is associated with high morbidity and mortality. CRKP can have multiple resistance mechanisms and only a few can be routinely detected by commercial molecular or phenotypic assays making surveillance for CRKP particularly challenging. In this report, we identified and characterized an unusual non–carbapenemase-producing CRKP carrying a rare plasmid-borne inducible AmpC gene, blaDHA-1. The isolate was recovered from blood culture of a 67-year-old female presenting with sepsis post bladder surgery and ureteral stent removal. The primary isolate displayed an indeterminate susceptibility pattern for ceftriaxone by broth microdilution, but was susceptible by disk diffusion with one colony growing within the zone of inhibition. The ceftriaxone resistant colony was sub-cultured and had a minimum inhibitory concentration (MIC) of 2 ug/ml for imipenem (intermediate) and a zone size of 18 mm for ertapenem (resistant), but remained susceptible to cefepime and meropenem. Further phenotypic characterization of this sub-cultured isolate showed carbapenemase activity. Whole genome sequencing (WGS) revealed the presence of two subpopulations of a K. pneumoniae (MLST sequence type 11) from the primary blood culture isolate: one pan-susceptible to beta-lactams tested and the other resistant to the 3rd generation cephalosporins and ertapenem. WGS analysis identified the resistant K. pneumoniae harboring IncFIB(K) and IncR plasmids and the presence of plasmid-borne beta-lactam resistance genes blaOXA-1 and blaDHA-1, an inducible AmpC gene. Additional resistance genes against quinolones (aac(6′)-Ib-cr, oqxA, oqB), aminoglycoside (aph(3′)-Ia), sulfonamide (sul1), and tetracycline (tet(A)) were also identified. DHA-1 positive K. pneumoniae have been previously identified outside the US, particularly in Asia and Europe, but limited cases have been reported in the United States and may be underrecognized. Our study highlights the importance of using both extended phenotypic testing and WGS to identify emerging resistance mechanisms in clinical Enterobacterales isolates with unusual antimicrobial resistance patterns.

scholarly journals High Frequency of Multidrug-resistant (Mdr) Klebsiella Pneumoniae Harboring Several β-lactamase and Integron Genes Collected From Several Hospitals in the North of Iran

2021 ◽  
Author(s):  
Mojgan Farhadi ◽  
Mohammad Ahanjan ◽  
Hamid Reza Goli ◽  
Mohammad Reza Haghshenas ◽  
Mehrdad Gholami
Keyword(s):  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
Antimicrobial Susceptibility ◽  
Hospitalized Patients ◽  
Clinical Samples ◽  
High Morbidity ◽  
Drug Resistant ◽  
The North ◽  
Agar Diffusion Test ◽  
North Of Iran

Abstract Background: Klebsiella pneumoniae is one of the leading causes of hospital outbreaks worldwide. Also, antibiotic-resistant K. pneumoniae is progressively being involved in invasive infections with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the incidences of resistance genes (integron types and β-lactamase-encoded genes) among clinical isolates of K. pneumoniae. Methods: In this cross-sectional study, a total of 100 clinical samples were obtained from hospitalized patients in three teaching hospitals in the north of Iran, from November 2018 and October 2019. Antimicrobial susceptibility testing was performed using disk agar diffusion test in line with CLSI recommendation. For colistin, minimum inhibitory concentration (MIC) was determined using broth microdilution. Based on antibiogram, multi-drug resistant (MDR) and extensive-drug resistant (XDR) strains were detected. Finally, integron types and β-lactamase resistance genes were identified using polymerase chain reaction technique.Results. The most and least clinical samples were related to the urine and bronchoalveolar lavage, respectively. Based on the antibiogram results, amikacin and gentamicin exhibited good activity against K. pneumoniae strains in vitro. High resistance rate (93%) to ampicillin/sulbactam also predict the limited efficacy of this antibiotic. Among all the 100 isolates, the frequency of MDR and XDR strains were 58% and 13%, respectively, while no pan-drug resistant (PDR) isolates were found. The prevalence of blaSHV, blaTEM, blaCTX-M-15, blaKPC, blaOXA-48, blaNDM β-lactamase genes were 91.4%, 82.7%, 79.3%, 29.3%, 36.2% and 6.9%, respectively, however 58% of the isolates were carrying intI gene. Class II and III integrons were not detected in any isolates. Conclusion: The MDR K. pneumoniae is becoming a serious problem in hospitals, with many strains developing resistance to most available antimicrobials. Our results indicate co-presence of a series of β-lactamase and integron types on the MDR strains recovered from hospitalized patients. The increasing rate of these isolates emphasizes the importance of choosing an appropriate antimicrobial regimen based on antibiotic susceptibility pattern.

scholarly journals Coexistence of aminoglycoside resistance genes in CTX-M-producing isolates of Klebsiella pneumoniae in Bushehr province, Iran

2021 ◽  
Author(s):  
Behrouz Latifi ◽  
Saeed Tajbakhsh ◽  
Leila Ahadi ◽  
Forough Yousefi
Keyword(s):  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
Confirmatory Test ◽  
M Gene ◽  
Aminoglycoside Resistance ◽  
Genetic Groups ◽  
Genes Encoding ◽  
Resistance Patterns ◽  
Aminoglycoside Resistance Genes ◽  
Antibiotic Resistance Patterns

Background and Objectives: Increasing the rate of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has given rise to a major healthcare issue in clinical settings over the past few years. Treatment of these strains is hardly effective since the plasmid encoding ESBL may also carry other resistance genes including aminoglycosides. The current study aimed to evaluate the prevalence of ESBL-producing K. pneumoniae and investigate the coexistence of Cefoxitamase-Munich (bla ) with aminoglycoside-modifying enzyme (AME) genes, aac(3)IIa as well as aac(6′)Ib, in CTX‑M‑producing K. pneumoniae isolated from patients in Bushehr province, Iran. Materials and Methods: A total of 212 K. pneumoniae isolates were collected and confirmed using polymerase chain re‑ action (PCR) of the malate dehydrogenase gene. Isolates were screened for production of ESBL. Phenotypic confirmatory test was performed using combined disk test. The genes encoding CTX-M groups and AME genes, aac(3)IIa and aac(6′)Ib, were investigated by PCR. Results: The ESBL phenotype was detected in 56 (26.4%) K. pneumoniae isolates. Moreover, 83.9% of ESBL-producing isolates carried the genes for CTX-M type β-lactamases, which were distributed into the two genetic groups of CTX-M-1 (97.8%)- and CTX-M-2 (2.1%)-related enzymes. Notably, among K. pneumoniae isolates containing the blaCTX‑M gene, 68.08% of isolates harbored AME genes. In addition, the coexistence of bla in 46.8% of CTX-M-producing K. pneumoniae isolates. Conclusion: This study provides evidence of a high prevalence of AME genes in CTX-M- producing K. pneumoniae iso‑ lates; therefore, in the initial empirical treatment of infections caused by ESBL-KP in regions with such antibiotic resistance patterns, aminoglycoside combination therapy should be undertaken carefully.

scholarly journals Molecular and phenotypic characterization of clinical isolates belonging to a KPC-2-producing strain of ST15 Klebsiella pneumoniae from a Vietnamese pediatric hospital

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Björn Berglund ◽  
Ngoc Thi Bich Hoang ◽  
Maria Tärnberg ◽  
Ngai Kien Le ◽  
Maud Nilsson ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
Resistance Rate ◽  
Clinical Isolates ◽  
Phenotypic Characterization ◽  
Polymorphism Analysis ◽  
Pediatric Hospital ◽  
Carbapenem Resistant ◽  
Global Epidemiology

Abstract Background Carbapenem-resistant Klebsiella pneumoniae are becoming increasingly common in hospital settings worldwide and are a source of increased morbidity, mortality and health care costs. The global epidemiology of carbapenem-resistant K. pneumoniae is characterized by different strains distributed geographically, with the strain ST258 being predominant in Europe and USA, and ST11 being most common in East Asia. ST15 is a less frequently occurring strain but has nevertheless been reported worldwide as a source of hospital outbreaks of carbapenem-resistant K. pneumoniae. Methods In this study, whole-genome sequencing and antimicrobial susceptibility testing was used to characterize 57 clinical isolates of carbapenem-resistant K. pneumoniae belonging to a strain of ST15, which were collected at a Vietnamese pediatric hospital from February throughout September 2015. Results Aside from the carbapenem resistance gene blaKPC-2, which was carried by all isolates, prevalence of resistance genes to other antibiotics including aminoglycosides, macrolides, quinolones, fosfomycin and trimethoprim, was also high. All isolates were multidrug-resistant. Susceptibility was highest to ceftazidime/avibactam (96%), gentamicin (91%) and tigecycline (82%). Notably, the colistin resistance rate was very high (42%). Single-nucleotide polymorphism analysis indicated that most isolates belonged to a single clone. Conclusions The diverse variety of antibiotic resistance genes and the high antibiotic resistance rates to last-resort antibiotics such as carbapenems and colistin, is indicative of a highly adaptable strain. This emphasizes the importance of implementation of infection controls measures, continued monitoring of antibiotic resistance and prudent use of antibiotics to prevent further selection of resistant strains and the emergence of pan-resistant clones.

Streptococcus pneumoniae: An Update on Resistance Patterns in the United States

2008 ◽  
Vol 21 (5) ◽  
pp. 363-370 ◽  
Author(s):  
Jessica A. Starr ◽  
Georgia W. Fox ◽  
Jennifer K. Clayton
Keyword(s):  
United States ◽  
Streptococcus Pneumoniae ◽  
Antimicrobial Agents ◽  
Respiratory Infections ◽  
Tetracycline Resistance ◽  
The United States ◽  
Multidrug Resistant ◽  
Beta Lactam ◽  
Resistance Patterns ◽  
Surveillance Programs

Streptococcus pneumoniae represents an important pathogen in numerous community-acquired respiratory infections. Penicillin resistance to Streptococcus pneumoniae in the United States has approached 35%. Additionally, there has been a significant increase in Streptococcus pneumoniae resistance among many other antimicrobial agents such as cephalosporins, macrolides, trimethoprim–sulfamethoxazole, clindamycin, tetracyclines, and chloramphenicol. Several nationwide surveillance programs have been implemented to quantify the prevalence of Streptococcus pneumoniae resistance in the United States. Overall, beta-lactam, macrolide, trimethoprim–sulfamethoxazole, and tetracycline resistance has increased over the past decade while later generation fluoroquinolones (levofloxacin and moxifloxacin) resistance has remained low. Controlling the spread of resistant pneumococcal isolates and preventing the development of both fluoroquinolone and multidrug resistant isolates will require a multidisciplinary approach involving physicians, pharmacists, microbiologists, and epidemiologists.

scholarly journals High frequency of multidrug-resistant (MDR) Klebsiella pneumoniae harboring several β-lactamase and integron genes collected from several hospitals in the north of Iran

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mojgan Farhadi ◽  
Mohammad Ahanjan ◽  
Hamid Reza Goli ◽  
Mohammad Reza Haghshenas ◽  
Mehrdad Gholami
Keyword(s):  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
Antimicrobial Susceptibility ◽  
Hospitalized Patients ◽  
Clinical Samples ◽  
High Morbidity ◽  
Drug Resistant ◽  
The North ◽  
Agar Diffusion Test ◽  
North Of Iran

Abstract Background Klebsiella pneumoniae is one of the leading causes of hospital outbreaks worldwide. Also, antibiotic-resistant K. pneumoniae is progressively being involved in invasive infections with high morbidity and mortality. The aim of the current study was to determine antimicrobial susceptibility patterns and the incidence of resistance genes (integron types and β-lactamase-encoded genes) among clinical isolates of K. pneumoniae. Methods In this cross-sectional study, a total of 100 clinical samples were obtained from hospitalized patients in three teaching hospitals in the north of Iran, from November 2018 and October 2019. Antimicrobial susceptibility testing was performed using disk agar diffusion test in line with CLSI recommendations. For colistin, minimum inhibitory concentration (MIC) was determined using broth microdilution. Based on antibiogram, multi-drug resistant (MDR) and extensive-drug resistant (XDR) strains were detected. Finally, integron types and β-lactamase resistance genes were identified using polymerase chain reaction technique. Results The most and least clinical samples were related to the urine and bronchoalveolar lavage, respectively. Based on the antibiogram results, amikacin and gentamicin exhibited good activity against K. pneumoniae strains in vitro. The high resistance rate (93%) to ampicillin/sulbactam predicts the limited efficacy of this antibiotic, in the hospitals studied. Among all the 100 isolates, the frequency of MDR and XDR phenotypes were 58% and 13%, respectively, while no pan-drug resistant (PDR) strains were found. In the MDR K. pneumoniae strains, the prevalence of blaSHV, blaTEM, blaCTX-M-15, blaKPC, blaOXA-48, blaNDM β-lactamase genes were 91.4%, 82.7%, 79.3%, 29.3%, 36.2% and 6.9%, respectively, however 91.4% of the isolates were carrying intI gene. Class II and III integrons were not detected in any isolates. Conclusion The MDR K. pneumoniae is becoming a serious problem in hospitals, with many strains developing resistance to most available antimicrobials. Our results indicate co-presence of a series of β-lactamase and integron types on the MDR strains recovered from hospitalized patients. The increasing rate of these isolates emphasizes the importance of choosing an appropriate antimicrobial regimen based on antibiotic susceptibility pattern.

scholarly journals Susceptibility testing of anaerobic bacteria: myth, magic, or method?

1991 ◽  
Vol 4 (4) ◽  
pp. 470-484 ◽  
Author(s):  
H M Wexler
Keyword(s):  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Anaerobic Bacteria ◽  
The United States ◽  
Resistance Mechanisms ◽  
National Committee ◽  
Test Results ◽  
Resistance Patterns ◽  
The Media ◽  
Elution Method

The demand for susceptibility testing of anaerobes has increased, yet consensus as to procedure and interpretation in this area has not been achieved. While routine testing of anaerobic isolates is not needed, certain isolates in specific clinical settings should be tested. Also, laboratories may monitor their local antibiograms by doing periodic surveillance batch testing. The National Committee for Clinical Laboratory Standards has published a protocol of methods approved for susceptibility testing of anaerobic bacteria. Both agar and broth microdilution are included; however, the broth disk elution method is no longer approved by the National Committee for Clinical Laboratory Standards because of method-related interpretive errors. A number of newer methods are undergoing evaluation and seem promising. Clinicians and microbiologists reviewing susceptibility reports should be aware of sources of variability in the test results. Variables in susceptibility testing of anaerobes include the media and methods used, organisms chosen for testing, breakpoints chosen for interpretation, antibiotic, and determination of endpoint. Clustering of MICs around the breakpoint may lead to significant variability in test results. Adherence of testing laboratories to approved methods and careful descriptions of the method and the breakpoints used for interpretation would facilitate interlaboratory comparisons and allow problems of emerging resistance to be noted. A variety of resistance mechanisms occurs in anaerobic bacteria, including the production of beta-lactamase and other drug-inactivating enzymes, alteration of target proteins, and inability of the drug to penetrate the bacterial wall. Antimicrobial resistance patterns in the United States and abroad are described.

scholarly journals Fusidic Acid Resistance Rates and Prevalence of Resistance Mechanisms among Staphylococcus spp. Isolated in North America and Australia, 2007-2008

2010 ◽  
Vol 54 (9) ◽  
pp. 3614-3617 ◽  
Author(s):  
Mariana Castanheira ◽  
Amy A. Watters ◽  
Jan M. Bell ◽  
John D. Turnidge ◽  
Ronald N. Jones
Keyword(s):  
United States ◽  
Resistance Genes ◽  
Fusidic Acid ◽  
Dominant Role ◽  
Acquired Resistance ◽  
Resistance Mechanism ◽  
Acid Resistance ◽  
The United States ◽  
Resistance Mechanisms ◽  
Resistance Rates

ABSTRACT Among 4,167 Staphylococcus aureus and 790 coagulase-negative Staphylococcus (CoNS; not S. saprophyticus) isolates collected consecutively from North American and Australian hospitals, only 87 (1.7% overall) isolates displayed a fusidic acid (FA; also known as CEM-102) MIC of ≥2 μg/ml (FA resistance). These strains were further evaluated with a multiplex PCR to amplify the acquired resistance genes fusB, fusC, and fusD. Mutations in fusA and fusE were evaluated in all isolates showing an absence of acquired resistance genes and/or showing FA MIC values of ≥64 μg/ml. S. aureus resistance rates were very low in the United States (0.3%) and were higher in Canada and Australia (7.0% for both countries). Among CoNS isolates, FA resistance rates were significantly more elevated than that for S. aureus (7.2 to 20.0%; the highest rates were in Canada). All 52 (41 CoNS) FA-resistant isolates from the United States showed FA MIC results of ≤64 μg/ml, and 7 of 11 S. aureus isolates carried fusC. CoNS strains from the United States carried fusB or fusC. In Canada, fusB and fusC occurrences were similar among S. aureus and CoNS isolates, and modestly elevated FA MIC values were observed (all MIC results were ≤32 μg/ml). Isolates from Australia showed MIC values ranging from 2 to 32 μg/ml, and S. aureus isolates were predominantly fusC positive. fusA mutations were detected in only three S. aureus isolates, conferring FA MIC values of 2 to 8 μg/ml. Target mutations have been considered the primary FA resistance mechanism among Staphylococcus spp.; however, acquired resistance genes appear to have a dominant role in resistance against this older antimicrobial agent. In summary, this study shows that acquired genes are highly prevalent among FA-resistant strains (>90%) in three nations with distinct or absence (United States) of fusidic acid clinical use.

scholarly journals 849. Whole Genome Sequencing Analysis of Klebsiella pneumoniae Isolates Reveals Diversity in Genetic Antibiotic Resistance Patterns

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S464-S466
Author(s):  
Ryan Beaver ◽  
Hosoon Choi ◽  
Chetan Jinadatha ◽  
Keith S Kaye ◽  
Piyali Chatterjee ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Klebsiella Pneumoniae ◽  
Resistance Genes ◽  
Veterans Affairs ◽  
Whole Genome ◽  
Department Of Veterans Affairs ◽  
Material Support ◽  
Resistance Patterns ◽  
Antibiotic Resistance Patterns ◽  
Research Grant

Abstract Background Klebsiella pneumoniae is among the leading causes of healthcare-associated infections (HAI). Multidrug-resistant (MDR) Klebsiella variants are difficult to treat and have been reported with increasing frequency in hospitals. Whole genome multi-locus sequence typing (wg-MLST) of K. pneumoniae HAI isolates was used to compare antibiotic resistance genetic patterns against epidemiologic typing. Figure 1. Prevalence of ABX resistance genes for each drug class. Figure 2. Prevalence of ABX resistance genes by hospital. Methods Forty-six clinical bacterial HAI isolates were collected from patients admitted to two disparate tertiary care hospitals in Detroit, Michigan between 2017 and 2019. Data output from wg-MLST was de novo assembled using SPAdes (version 3.7.1) assembler on the Bionumerics calculation engine. Minimum spanning tree (MST) analysis categorized isolates into unique MLST Pasteur serotypes (ST). Antimicrobial resistance genes and/or chromosomal mutations were identified using the ResFinder Database (version 3.2). K. pneumoniae isolates were compared for antibiotic-resistance patterns by hospital, unit, and ST. Figure 3. Hospital 1 clusters and strains that detected gene qnr1, arranged by unit for visual comparison. Figure 4. Sample of clinically significant genes and prevalence, excluding SHV family of genes for simplicity. Results There was significant genetic diversity among the isolates, and no predominant strain was identified. MST analysis revealed 17 unique strains. Only six strains had genetically unique resistance genes detected in more than one isolate, and only three of six were hospital-specific; none were unit-specific. Out of the 75 unique resistance genes detected, only 8 genes had a prevalence >50%: oqxA (100%), oqxB (100%), fosA (89%), blaCTX-M-15 (76%), aac(6’)-Ib-cr (61%), blaTEM-1B (52%), blaOXA-1 (52%), and catB3 (52%). No colistin resistance genes were detected. Of the remaining 69 low-prevalence resistance genes, only 8 hospital-specific genes were detected in more than one isolate (qnrB1, blaSHV-1, blaSHV-110, ac(6’)-Ib3, blaCTX-M-3, blaSHV-36, blaSHV-80, blaSHV-178) with a prevalence range of 4%-22%. Conclusion Our genetic analysis of antibiotic resistance patterns and wg-MLST revealed significant heterogeneity among the isolates, indicating no common source of transmission for either hospital. Although K. pneumoniae is a very common nosocomial pathogen, etiologic analysis suggests diverse community strains (e.g., gut colonization) may actually be responsible for previously-designated HAI. Disclosures Chetan Jinadatha, MD, MPH, AHRQ (Research Grant or Support)Department of Veterans Affairs (Other Financial or Material Support, Owner: Department of Veterans Affairs. Licensed to: Xenex Disinfection System, San Antonio, TX)Inventor (Other Financial or Material Support, Methods for organizing the disinfection of one or more items contaminated with biological agents)NiH/NINR (Research Grant or Support)NSF (Research Grant or Support)Xenex Healthcare Services (Research Grant or Support) Mark Stibich, PhD MHS, Xenex Disinfection Services, Inc (Board Member, Employee)

scholarly journals Virulence Factors, Antibiotic Resistance patterns, and Molecular Types of Clinical Isolates of Klebsiella Pneumoniae

2021 ◽  
Author(s):  
Mitra Ahmadi ◽  
Payam Behzadi ◽  
Reza Ranjbar
Keyword(s):  
Antibiotic Resistance ◽  
Klebsiella Pneumoniae ◽  
Molecular Typing ◽  
Virulence Genes ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Aminoglycoside Resistance ◽  
Wide Range ◽  
Resistance Patterns ◽  
Esbl Producers

Abstract Background Klebsiella pneumoniae is armed with a wide range of antibiotic resistance mechanisms which mostly challenges effective treatment. Due to this fact, the aims of the current study were to identify the clinical strains of K . pneumoniae as well as to determine their phenotypes and molecular characterization related to antimicrobial resistance and virulence genes. Methods In this investigation, specimens from a hospital and different laboratories located in Shahr-e-Qods, Tehran, Iran were collected during a period of nine-month (December 2018 to August 2019). The isolated strains of K. pneumoniae were then identified through standard microbial and biochemical assays. Additionally, disk diffusion, combined disk, modified Hodge test and PCR were performed for antibiotic resistance of the strains and virulence genes profiling, respectively. The molecular typing was accomplished by ERIC-PCR. Results Eighty-four isolates of K. pneumoniae were identified and subjected to the study. Fifty- two percent of the isolated strains of K. pneumoniae were detected as multidrug resistant (MDR) pathotypes with the highest resistance to ceftriaxone (65%) and the lowest resistance to colistin (23%). Twenty-seven (52%) out of 52 (100%) MDR pathotypes of isolated K. pneumoniae were identified as ESBL producers. According to Modified Hodge Test (MHT) results, out of 24 resistant strains of isolated K. pneumoniae to imipenem and meropenem, 15 pathotypes (62.5%) were detected as KPC producers. The gene of blaCTX (encoding carbapenemase) with 96% ranked first, while the blaKPC gene with the prevalence of 71% ranked second among ESBL producers. The aminoglycoside resistance gene of Aac6-Ib showed the highest frequency with the prevalence percentage of 90%. The virulence genes of mrkD (94%) and magA (11%) were the highest and lowest among isolates, respectively. According to ERIC-PCR results the isolated strains of K. pneumoniae were divided into four clusters in which the cluster 4 was predominant group. Conclusions The high prevalence of antibiotic resistance and virulence genes in conjunction with a significant relationship between the strains reveals a high pathogenic capacity of the isolated pathotypes of K. pneumoniae . These findings emphasize the choose of more effective antibiotic regimens for treatment of infections caused by K. pneumoniae. Keywords: Klebsiella pneumoniae , antibiotic resistance, ESBL, virulence genes, molecular typing.

scholarly journals Microbiological and molecular characteristics of carbapenemase-producing Klebsiella pneumoniae endemic in a tertiary Greek hospital during 2004-2010

2012 ◽  
Vol 17 (7) ◽  
Author(s):  
A Zagorianou ◽  
E Sianou ◽  
E Iosifidis ◽  
V Dimou ◽  
E Protonotariou ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Infection Control ◽  
Antibiotic Use ◽  
The United States ◽  
Tertiary Hospital ◽  
Control Measures ◽  
Molecular Characteristics ◽  
Beta Lactam ◽  
Beta Lactam Antibiotics ◽  
Infection Control Measures

We report 570 carbapenemase-producing Klebsiella pneumoniae (CPKP) clinical isolates in a 1,040-bed Greek tertiary hospital during 2004 to 2010. The first CPKP (VIM-producing) was isolated in September 2004. Despite initial containment, VIM producers have become endemic since 2006. KPC-producing K. pneumoniae was first isolated in August 2007 from a patient who came from Israel, spread rapidly, and outcompeted VIM. Overall, 267 (47%) VIM-producing and 301 (53%) KPC-producing strains were isolated, including 141 (24.7%) from patients with bacteraemia. Two isolates carrying both VIM and KPC were isolated in two consecutive months in 2009, but not since. The prevalence of CPKP increased from 0% in 2003 to 38.3% in 2010 (p<0.0001). All genotyped KPC producers harboured blaKPC-2 and belonged to two clones, among which the hyperepidemic Greek clone, related to those from the United States and Israel, predominated. Most metallo-beta-lactamase (MBL) producers carried the blaVIM-1 gene and belonged to several clones, whereas all but one isolate with blaVIM-12 were clustered within a five-month period, arising from one clone. Resistance to non-beta-lactam antibiotics was also increased among CPKP. They were almost invariably resistant to ciprofloxacin and trimethoprim-sulfamethoxazole. Resistance to colistin increased from 3.5% (4/115) in 2008 to 20.8% (25/120) in 2010, and resistance to tigecycline also increased. Following reinforcement of infection control measures, prevalence of CPKP (mainly KPC) has been reduced since mid-2009 (from 46% in 2009 to 38.3% in 2010). In view of the exhaustion of available therapies, investment in infection control resources and optimal antibiotic use is urgently required.

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