Genotypic Diversity, Antimicrobial Resistance, and Virulence Factors of Human Isolates and Probiotic Cultures Constituting Two Intraspecific Groups of Enterococcus faecium Isolates

ABSTRACTThe intraspecific relationships among a collection ofEnterococcus faeciumisolates comprising probiotic cultures and human clinical isolates were investigated through the combined use of two high-resolution DNA-fingerprinting techniques. In addition, the incidences of antimicrobial resistance and virulence traits were investigated. A total of 128E. faeciumisolates from human clinical or nonclinical sources or used as probiotic cultures were subjected to fluorescent amplified fragment length polymorphism (FAFLP) fingerprinting and pulsed-field gel electrophoresis (PFGE) analysis of SmaI macrorestriction patterns. Susceptibilities to 16 antimicrobial agents were tested using broth microdilution, and the presence of the corresponding resistance genes was investigated using PCR. Multiplex PCR was used to detect the presence of the enterococcal virulence genesasa1,gelE,cylA,esp, andhyl. The results of the study showed that two intraspecific genomic groups (I and II) were obtained in FAFLP analysis. PFGE analysis demonstrated high variability within these two groups but also indicated that some probiotic cultures were indistinguishable and that a number of clinical isolates may be reisolations of commercial probiotic cultures. Compared to group II, which contained the majority of the probiotic isolates and fewer human clinical isolates, higher phenotypic and genotypic resistance frequencies were observed in group I. Two probiotic isolates were phenotypically resistant to erythromycin, one of which contained anerm(B) gene that was not transferable to enterococcal recipients. None of the probioticE. faeciumisolates demonstrated the presence of the tested virulence genes. The previously reported observation thatE. faeciumconsists of two intraspecific genomic groups was further substantiated by FAFLP fingerprinting of 128 isolates. In combination with antimicrobial resistance and virulence testing, this grouping might represent an additional criterion in assessing the safety of new potential probioticE. faeciumisolates.

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Antimicrobial resistance and molecular epidemiology of virulence genes among multi-drug resistant clinical isolates in Iran

Gene Reports ◽

10.1016/j.genrep.2021.101281 ◽

2021 ◽

pp. 101281

Author(s):

Mohammadreza Sadr ◽

Seyed Alireza Fahimzad ◽

Abdollah Karimi ◽

Fatemeh Fallah ◽

Shahnaz Armin ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Molecular Epidemiology ◽

Virulence Genes ◽

Clinical Isolates ◽

Drug Resistant

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Genotyping and antimicrobial resistance in Escherichia coli from pig carcasses

Pesquisa Veterinária Brasileira ◽

10.1590/s0100-736x2017001100010 ◽

2017 ◽

Vol 37 (11) ◽

pp. 1253-1260 ◽

Cited By ~ 1

Author(s):

Caroline Pissetti ◽

Gabriela Orosco Werlang ◽

Jalusa Deon Kich ◽

Marisa Cardoso

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Antimicrobial Agents ◽

Commensal Bacteria ◽

Pfge Analysis ◽

Gene Detection ◽

E Coli ◽

Antimicrobial Resistance Profile ◽

Resistant Strains ◽

Pig Carcasses

ABSTRACT: The increasing antimicrobial resistance observed worldwide in bacteria isolated from human and animals is a matter of extreme concern and has led to the monitoring of antimicrobial resistance in pathogenic and commensal bacteria. The aim of this study was to evaluate the antimicrobial resistance profile of Escherichia coli isolated from pig carcasses and to assess the occurrence of relevant resistance genes. A total of 319 E. coli isolates were tested for antimicrobial susceptibility against different antimicrobial agents. Moreover, the presence of extended-spectrum β-lactamase (ESBL) and inducible ampC-β-lactamase producers was investigated. Eighteen multi-resistant strains were chosen for resistance gene detection and PFGE characterization. The study showed that resistance to antimicrobials is widespread in E. coli isolated from pig carcasses, since 86.2% of the strains were resistant to at least one antimicrobial and 71.5% displayed multi-resistance profiles. No ampC-producing isolates were detected and only one ESBL-producing E. coli was identified. Genes strA (n=15), floR (n=14), aac(3)IVa (n=13), tetB (n=13), sul2 (n=12), tetA (n=11), aph(3)Ia (n=8) and sul3 (n=5) were detected by PCR. PFGE analysis of these multi-resistant E. coli strains showed less than 80% similarity among them. We conclude that antimicrobial multi-resistant E. coli strains are common on pig carcasses and present highly diverse genotypes and resistance phenotypes and genotypes.

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Molecular characterisation of antimicrobial resistance and virulence genes in Escherichia coli strains isolated from diarrhoeic and healthy rabbits in Tunisia

World Rabbit Science ◽

10.4995/wrs.2020.10879 ◽

2020 ◽

Vol 28 (2) ◽

pp. 81

Author(s):

Raouia Ben Rhouma ◽

Ahlem Jouini ◽

Amira Klibi ◽

Safa Hamrouni ◽

Aziza Boubaker ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Virulence Genes ◽

Antimicrobial Agents ◽

Antibiotic Resistance Genes ◽

Virulence Gene ◽

Diffusion Method ◽

Class 1 Integron ◽

E Coli ◽

Class 1

The purpose of this study was to identify Escherichia coli isolates in diarrhoeic and healthy rabbits in Tunisia and characterise their virulence and antibiotic resistance genes. In the 2014-2015 period, 60 faecal samples from diarrhoeic and healthy rabbits were collected from different breeding farms in Tunisia. Susceptibility to 14 antimicrobial agents was tested by disc diffusion method and the mechanisms of gene resistance were evaluated using polymerase chain reaction and sequencing methods. Forty E. coli isolates were recovered in selective media. High frequency of resistance to tetracycline (95%) was detected, followed by different levels of resistance to sulphonamide (72.5%), streptomycin (62.5%), trimethoprim-sulfamethoxazole (60%), nalidixic acid (32.5%), ampicillin (37.5%) and ticarcillin (35%). E. coli strains were susceptible to cefotaxime, ceftazidime and imipenem. Different variants of blaTEM, tet, sul genes were detected in most of the strains resistant to ampicillin, tetracycline and sulphonamide, respectively. The presence of class 1 integron was studied in 29 sulphonamide-resistant E. coli strains from which 15 harboured class 1 integron with four different arrangements of gene cassettes, dfrA17+aadA5 (n=9), dfrA1 + aadA1 (n=4), dfrA12 + addA2 (n=1), dfrA12+orf+addA2 (n=1). The qnrB gene was detected in six strains out of 13 quinolone-resistant E. coli strains. Seventeen E. coli isolates from diarrhoeic rabbits harboured the enteropathogenic eae genes associated with different virulence genes tested (fimA, cnf1, aer), and affiliated to B2 (n=8) and D (n=9) phylogroups. Isolated E. coli strains from healthy rabbit were harbouring fim A and/or cnf1 genes and affiliated to A and B1 phylogroups. This study showed that E. coli strains from the intestinal tract of rabbits are resistant to the widely prescribed antibiotics in medicine. Therefore, they constitute a reservoir of antimicrobial-resistant genes, which may play a significant role in the spread of antimicrobial resistance. In addition, the eae virulence gene seemed to be implicated in diarrhoea in breeder rabbits in Tunisia.

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Retrospective Analysis on Antimicrobial Resistance Trends and Prevalence of β-lactamases in Escherichia coli and ESKAPE Pathogens Isolated from Arabian Patients during 2000–2020

Microorganisms ◽

10.3390/microorganisms8101626 ◽

2020 ◽

Vol 8 (10) ◽

pp. 1626

Author(s):

Mahfouz Nasser ◽

Snehal Palwe ◽

Ram Naresh Bhargava ◽

Marc G. J. Feuilloley ◽

Arun S. Kharat

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Antimicrobial Resistance ◽

Enterococcus Faecium ◽

Arab Countries ◽

Clinical Isolates ◽

Arab Region ◽

E Coli ◽

Extended Spectrum ◽

Eskape Pathogens

The production of diverse and extended spectrum β-lactamases among Escherichia coli and ESKAPE pathogens is a growing threat to clinicians and public health. We aim to provide a comprehensive analysis of evolving trends of antimicrobial resistance and β-lactamases among E. coli and ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acine to bacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) in the Arabian region. A systematic review was conducted in Medline PubMed on papers published between January 2000 and February 2020 on countries in the Arab region showing different antibiotic resistance among E. coli and ESKAPE pathogens. A total of n = 119,144 clinical isolates were evaluated for antimicrobial resistance in 19 Arab countries. Among these clinical isolates, 74,039 belonged to E. coli and ESKAPE pathogen. Distribution of antibiotic resistance among E. coli and ESKAPE pathogens indicated that E. coli (n = 32,038) was the predominant pathogen followed by K. pneumoniae (n = 17,128), P. aeruginosa (n = 11,074), methicillin-resistant S. aureus (MRSA, n = 4370), A. baumannii (n = 3485) and Enterobacter spp. (n = 1574). There were no reports demonstrating Enterococcus faecium producing β-lactamase. Analyses revealed 19 out of 22 countries reported occurrence of ESBL (Extended-Spectrum β-Lactamase) producing E. coli and ESKAPE pathogens. The present study showed significantly increased resistance rates to various antimicrobial agents over the last 20 years; for instance, cephalosporin resistance increased from 37 to 89.5%, fluoroquinolones from 46.8 to 70.3%, aminoglycosides from 40.2 to 64.4%, mono-bactams from 30.6 to 73.6% and carbapenems from 30.5 to 64.4%. An average of 36.9% of the total isolates were reported to have ESBL phenotype during 2000 to 2020. Molecular analyses showed that among ESBLs and Class A and Class D β-lactamases, blaCTX-M and blaOXA have higher prevalence rates of 57% and 52.7%, respectively. Among Class B β-lactamases, few incidences of blaVIM 27.7% and blaNDM 26.3% were encountered in the Arab region. Conclusion: This review highlights a significant increase in resistance to various classes of antibiotics, including cephalosporins, β-lactam and β-lactamase inhibitor combinations, carbapenems, aminoglycosides and quinolones among E. coli and ESKAPE pathogens in the Arab region.

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Molecular detection of biofilm, virulence and antimicrobial resistance associated genes of Salmonella serovars isolated from pig and chicken of Mizoram, India

Indian Journal of Animal Research ◽

10.18805/ijar.b-3817 ◽

2019 ◽

Author(s):

S. Chakraborty ◽

P. Roychoudhury ◽

I. Samanta ◽

P. K. Subudhi ◽

Lalhruaipuii Lalhruaipuii ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Virulence Genes ◽

Antimicrobial Agents ◽

Virulence Gene ◽

Microtiter Plate ◽

Multidrug Resistant ◽

Salmonella Spp ◽

Microtiter Plate Assay ◽

Antimicrobial Sensitivity ◽

Salmonella Infections

Salmonella has emerged as one of the most important food-borne pathogens for humans as well as animals and the ability of biofilm formation by these bacteria has further aided their survival in unfavorable environment. Characterization of these biofilm producing bacteria isolated from pigs and chicken may lead to formulation of strategies for prevention and control of Salmonella infections. Therefore, the present study was conducted to isolate Salmonella from pigs and poultry of Mizoram, determine their biofilm producing ability by phenotypic and genotypic methods along with their virulence and antimicrobial resistance properties. A total of 15 Salmonella spp. (pig=9, poultry=6) was isolated from 100 faecal samples from pigs and 50 cloacal swabs from poultry and biofilm producing ability of the isolates was determined by microtiter plate assay. A total of 10 (66.67%) isolates were found to be biofilm producer. All the biofilm producing bacterial isolates were investigated for antimicrobial sensitivity and distribution of selected biofilm associated genes (csgA, csgD and adrA), virulence genes (invA, stn and sefA) and antimicrobial resistance (AMR) genes (blaTEM, blaSHV and blaCTX-M). The most prevalent resistance was found against ceftazidime (80%), ceftriaxone (80%), cefixime (70%), cefotaxime (70%), gentamicin (70%), cotrimoxazole (60%) and ampicillin (60%). A total of 7 (70%) isolates were resistant to at least three different classes of antimicrobial agents and considered as multidrug resistant. All the isolates were positive for adrA (100%) but negative for csgA and csgD genes. The most frequent virulence gene was invA (100%) and stn (100%). Among the AMR genes, blaTEM (60%) was found to be the major AMR determinants. Moreover, a total of 7 Salmonella isolates were positive for at least one of t biofilm associated genes, virulence genes and AMR genes.

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In vitro activity of new antimicrobial agents against glycopeptide-resistant Enterococcus faecium clinical isolates from France between 2006 and 2008

Médecine et Maladies Infectieuses ◽

10.1016/j.medmal.2010.12.013 ◽

2011 ◽

Vol 41 (8) ◽

pp. 405-409 ◽

Cited By ~ 12

Author(s):

R. Bérenger ◽

N. Bourdon ◽

M. Auzou ◽

R. Leclercq ◽

V. Cattoir

Keyword(s):

Enterococcus Faecium ◽

Antimicrobial Agents ◽

Vitro Activity ◽

Clinical Isolates ◽

In Vitro Activity

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Molecular epidemiology and antimicrobial resistance features of Acinetobacter baumannii clinical isolates from Pakistan

Annals of Clinical Microbiology and Antimicrobials ◽

10.1186/s12941-019-0344-7 ◽

2020 ◽

Vol 19 (1) ◽

Cited By ~ 2

Author(s):

Nabil Karah ◽

Fizza Khalid ◽

Sun Nyunt Wai ◽

Bernt Eric Uhlin ◽

Irfan Ahmad

Keyword(s):

Antimicrobial Resistance ◽

Molecular Epidemiology ◽

Acinetobacter Baumannii ◽

Resistance Genes ◽

Antimicrobial Agents ◽

Opportunistic Pathogen ◽

Clinical Isolates ◽

Diffusion Method ◽

Agar Disc ◽

Antimicrobial Resistance Genes

Abstract Background Acinetobacter baumannii is a Gram-negative opportunistic pathogen with a notorious reputation of being resistant to antimicrobial agents. The capability of A. baumannii to persist and disseminate between healthcare settings has raised a major concern worldwide. Methods Our study investigated the antibiotic resistance features and molecular epidemiology of 52 clinical isolates of A. baumannii collected in Pakistan between 2013 and 2015. Antimicrobial susceptibility patterns were determined by the agar disc diffusion method. Comparative sequence analyses of the ampC and blaOXA-51-like alleles were used to assign the isolates into clusters. The whole genomes of 25 representative isolates were sequenced using the MiSeq Desktop Sequencer. Free online applications were used to determine the phylogeny of genomic sequences, retrieve the multilocus sequence types (ST), and detect acquired antimicrobial resistance genes. Results Overall, the isolates were grouped into 7 clusters and 3 sporadic isolates. The largest cluster, Ab-Pak-cluster-1 (blaOXA-66 and ISAba1-ampC-19) included 24 isolates, belonged to ST2 and International clone (IC) II, and was distributed between two geographical far-off cities, Lahore and Peshawar. Ab-Pak-clusters-2 (blaOXA-66, ISAba1-ampC-2), and -3 (blaOXA-66, ISAba1-ampC-20) and the individual isolate Ab-Pak-Lah-01 (ISAba1-blaOXA-66, ISAba1-ampC-2) were also assigned to ST2 and IC II. On the other hand, Ab-Pak-clusters-4 (blaOXA-69, ampC-1), -5 (blaOXA-69, ISAba1-ampC-78), and -6A (blaOXA-371, ISAba1-ampC-3) belonged to ST1, while Ab-Pak-cluster-6B (blaOXA-371, ISAba1-ampC-8) belonged to ST1106, with both ST1 and ST1106 being members of IC I. Five isolates belonged to Ab-Pak-cluster-7 (blaOXA-65, ampC-43). This cluster corresponded to ST158, showed a well-delineated position on the genomic phylogenetic tree, and was equipped with several antimicrobial resistance genes including blaOXA-23 and blaGES-11. Conclusions Our study detected the occurrence of 7 clusters of A. baumannii in Pakistan. Altogether, 6/7 of the clusters and 45/52 (86.5%) of the isolates belonged to IC I (n = 9) or II (n = 36), making Pakistan no exception to the global domination of these two clones. The onset of ST158 in Pakistan marked a geographical dispersal of this clone beyond the Middle East and brought up the need for a detailed characterization.

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Detection of the Phenicol–Oxazolidinone Resistance Gene poxtA in Enterococcus faecium and Enterococcus faecalis from Food-Producing Animals during 2008–2018 in Korea

Microorganisms ◽

10.3390/microorganisms8111839 ◽

2020 ◽

Vol 8 (11) ◽

pp. 1839

Author(s):

Seok-Hyeon Na ◽

Dong-Chan Moon ◽

Mi-Hyun Kim ◽

Hee-Young Kang ◽

Su-Jeong Kim ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Ribosomal Protein ◽

Resistance Gene ◽

Enterococcus Faecalis ◽

Enterococcus Faecium ◽

Gel Electrophoresis ◽

Pulsed Field Gel Electrophoresis ◽

Molecular Characteristics ◽

Pfge Analysis ◽

Linezolid Resistance

We aimed to investigate the presence of the phenicol–oxazolidinone resistance gene poxtA in linezolid-resistant enterococci from food-producing animals and analyze its molecular characteristics. We collected 3941 Enterococcus faecium and 5088 E. faecalis isolates from all provinces of South Korea from 2008 to 2018. We found linezolid resistance in 0.79% (94/3941) of E. faecium and 1.22% (62/5088) of E. faecalis isolates. Overall, 23.1% (36/156) of the linezolid-resistant isolates had the poxtA gene, including 31 E. faecium and five E. faecalis isolates. The poxtA-positive enterococci were mainly isolated from chicken (86.1%; 26/36). Fifteen poxtA-harboring isolates co-carried another linezolid-resistance gene, optrA. Eight E. faecium isolates had an N130K mutation in the ribosomal protein L4, while no mutations were observed in E. faecalis isolates. The poxtA gene was transferred into 10 enterococci by conjugation. Multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE) analysis indicated that poxtA-carrying isolates were heterogeneous. Three E. faecium isolates belonged to CC17 (ST32, ST121, and ST491). To our knowledge, this is the first report on the poxtA gene in Korea. Prudent use of antimicrobials and active surveillance on antimicrobial resistance are urgently needed to reduce the risk of dissemination of the linezolid-resistant isolates in humans and animals.

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628. Integrated Surveillance for Antimicrobial-Resistance in Salmonella From Clinical and Retail Meat Sources—Pennsylvania, 2015–2017

Open Forum Infectious Diseases ◽

10.1093/ofid/ofz360.696 ◽

2019 ◽

Vol 6 (Supplement_2) ◽

pp. S291-S292

Author(s):

Nkuchia M M’ikanatha ◽

Kelly E Kline ◽

Sameh W Boktor ◽

Xin Yin ◽

Lisa Dettinger ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Foodborne Pathogens ◽

Antimicrobial Agents ◽

Multidrug Resistant ◽

Clinical Isolates ◽

Food Sources ◽

Health Concern ◽

Animal Origin ◽

Extended Spectrum ◽

Amoxicillin Clavulanate

Abstract Background Antimicrobial resistance (AMR) in foodborne pathogens of animal origin, including nontyphoidal Salmonella (NTS), is a public health concern. Pennsylvania conducts integrated surveillance for AMR in NTS from human and animal sources in collaboration with the FDA and CDC National Antimicrobial Resistant Monitoring System (NARMS). Methods We reviewed pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility (SST) and whole-genome sequencing (WGS) data for isolates from animal and food sources, including 96 NTS from 2,520 meat samples (poultry, ground beef and pork chops) purchased during 2015–2017 from randomly selected retail outlets in Pennsylvania. SST to 15 antimicrobial agents was done on 109 NTS clinical isolates that had similar PFGE patterns to meat isolates. SST and WGS were used to characterize all isolates from meat and two clinical isolates from 2017. Results 28 (29.2%) and 17 (17.7%) NTS isolated from meat sources were resistant to ≥3 and ≥5 antibiotics classes, respectively. Resistance to ceftriaxone rose from 12% (3/25) in 2015 to 27% (10/37) in 2016 and resistance to amoxicillin/clavulanate also increased. Plasmid-mediated bla CMY-2 β-lactam resistance genes that hydrolyze extended-spectrum cephalosporins (ESC) increased from 12% in 2015 (3/25) to 18.9% (7/37) in 2016. Four blaCTX-M-65 genes that confer resistance to extended-spectrum β-lactamases (ESBLs) were identified in 2016 (n = 3) and 2017. Of the 109 clinical isolates, 25.7% demonstrated resistance to ≥3 and 11% to ≥5 antibiotics classes, respectively. No clinical isolates were resistant to ceftriaxone in 2015, 12.5% (6/48) and 24.3% (9/37) were resistant in 2016 and 2017, respectively. Resistance to amoxicillin/clavulanate was demonstrated in 8.3% (4/48) of isolates in 2016 (figure). Two clinical isolates carried blaCTX-M-65 ESB Ls genes and were resistant to eight antimicrobial agents (ACSSuTCxNalCot. Phenotype). Conclusion NTS (≥25%) from animal and human sources were multidrug-resistant and harbored CMY-2 and CTX-M-65 genes. Dissemination of genes that confer resistance to ESBLs and ESCs in NTS undermines recommended treatment for severe infections and underscores the need for One-Health surveillance and antimicrobial stewardship efforts. Disclosures All authors: No reported disclosures.

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Antimicrobial Resistance among Clinical Isolates ofStreptococcus pneumoniae in the United States during 1999–2000, Including a Comparison of Resistance Rates since 1994–1995

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.45.6.1721-1729.2001 ◽

2001 ◽

Vol 45 (6) ◽

pp. 1721-1729 ◽

Cited By ~ 390

Author(s):

Gary V. Doern ◽

Kristopher P. Heilmann ◽

Holly K. Huynh ◽

Paul R. Rhomberg ◽

Stacy L. Coffman ◽

...

Keyword(s):

United States ◽

Antimicrobial Resistance ◽

Antimicrobial Agents ◽

Rank Order ◽

The United States ◽

Clinical Isolates ◽

Beta Lactam ◽

High Level ◽

Resistance Rates

ABSTRACT A total of 1,531 recent clinical isolates of Streptococcus pneumoniae were collected from 33 medical centers nationwide during the winter of 1999–2000 and characterized at a central laboratory. Of these isolates, 34.2% were penicillin nonsusceptible (MIC ≥ 0.12 μg/ml) and 21.5% were high-level resistant (MIC ≥ 2 μg/ml). MICs to all beta-lactam antimicrobials increased as penicillin MICs increased. Resistance rates among non-beta-lactam agents were the following: macrolides, 25.2 to 25.7%; clindamycin, 8.9%; tetracycline, 16.3%; chloramphenicol, 8.3%; and trimethoprim-sulfamethoxazole (TMP-SMX), 30.3%. Resistance to non-beta-lactam agents was higher among penicillin-resistant strains than penicillin-susceptible strains; 22.4% of S. pneumoniae were multiresistant. Resistance to vancomycin and quinupristin-dalfopristin was not detected. Resistance to rifampin was 0.1%. Testing of seven fluoroquinolones resulted in the following rank order of in vitro activity: gemifloxacin > sitafloxacin > moxifloxacin > gatifloxacin > levofloxacin = ciprofloxacin > ofloxacin. For 1.4% of strains, ciprofloxacin MICs were ≥4 μg/ml. The MIC90s (MICs at which 90% of isolates were inhibited) of two ketolides were 0.06 μg/ml (ABT773) and 0.12 μg/ml (telithromycin). The MIC90 of linezolid was 2 μg/ml. Overall, antimicrobial resistance was highest among middle ear fluid and sinus isolates of S. pneumoniae; lowest resistance rates were noted with isolates from cerebrospinal fluid and blood. Resistant isolates were most often recovered from children 0 to 5 years of age and from patients in the southeastern United States. This study represents a continuation of two previous national studies, one in 1994–1995 and the other in 1997–1998. Resistance rates with S. pneumoniae have increased markedly in the United States during the past 5 years. Increases in resistance from 1994–1995 to 1999–2000 for selected antimicrobial agents were as follows: penicillin, 10.6%; erythromycin, 16.1%; tetracycline, 9.0%; TMP-SMX, 9.1%; and chloramphenicol, 4.0%, the increase in multiresistance was 13.3%. Despite awareness and prevention efforts, antimicrobial resistance with S. pneumoniae continues to increase in the United States.

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