Changing Patterns Of Antimicrobial Resistance Research Articles

Streptococcus pneumoniae serotyping and antimicrobial susceptibility: assessment for vaccine efficacy in Canada after the introduction of PCV13.

Streptococcus pneumoniae continues to be an important bacterial pathogen associated with invasive (e.g. bacteraemia, meningitis) and non-invasive (e.g. community-acquired respiratory tract) infections worldwide. Surveillance studies conducted nationally and globally assist in determining trends over geographical areas and allow comparisons between countries. To characterize invasive isolates of S. pneumoniae in terms of their serotype, antimicrobial resistance, genotype and virulence and to use the serotype data to determine the level of coverage by different generations of pneumococcal vaccines. SAVE (Streptococcus pneumoniae Serotyping and Antimicrobial Susceptibility: Assessment for Vaccine Efficacy in Canada) is an ongoing, annual, national collaborative study between the Canadian Antimicrobial Resistance Alliance (CARE) and the National Microbiology Laboratory, focused on characterizing invasive isolates of S. pneumoniae obtained across Canada. Clinical isolates from normally sterile sites were forwarded by participating hospital public health laboratories to the Public Health Agency of Canada-National Microbiology Laboratory and CARE for centralized phenotypic and genotypic investigation. The four articles in this Supplement provide a comprehensive examination of the changing patterns of antimicrobial resistance and MDR, serotype distribution, genotypic relatedness and virulence of invasive S. pneumoniae obtained across Canada over a 10 year period (2011-2020). The data highlight the evolution of S. pneumoniae under pressure by vaccination and antimicrobial usage, as well as vaccine coverage, allowing both clinicians and researchers nationally and globally to view the current status of invasive pneumococcal infections in Canada.

Alarming Pattern of Antimicrobial Resistance in Neonatal Sepsis Observed in Neonatal Intensive Care Unit of a Tertiary Care Hospital in Bangladesh

Background: Resistance of micro-organisms to multiple broad-spectrum antimicrobial agents is a major problem in treating neonatal sepsis. It is a matter of utmost importance to have knowledge of trends in changing pattern of antimicrobial resistance.
 Objective: This study was done to observe antimicrobial resistance of gram-positive and gram-negative bacteria isolated from cases of neonatal sepsis
 Material and Methods: This cross sectional descriptive study was conducted in Department of Microbiology in collaboration with Department of Neonatology, Dhaka Medical College Hospital, Dhaka. Antimicrobial resistance of all the isolated bacteria was performed by Modified Kirby-bauer disk diffusion method following standard guideline after isolation and identification of bacteria from blood samples of suspected septicemic neonates by automated blood culture and standard microbiological protocol.
 Results: All of the isolated Staphylococcus aureus, Coagulase negative Staphylococcus, Group-B Streptococcus and Micrococcus showed 100% resistance to ceftriaxone, cefotaxime and ceftazidime. Among the isolated gram-negative bacteria, all of Enterobacter spp., Pseudomonas aeruginosa and Citrobacter spp. showed 100% resistance to amoxiclav, amikacin, ceftriaxone, cefixime, ceftazidime.
 Conclusion: Majority of the gram-positive and gram-negative bacteria are developing resistance to multiple antimicrobial agents and surveillance is necessary to tackle this alarming situation.
 KYAMC Journal.2021;12(01): 03-07

Changing pattern of antimicrobial resistance in clinical isolates from pyogenic infections in tertiary care hospital at Western Rajasthan, India

Background: Pyogenic wound infections are one of the most common clinical entities caused and aggravated by the invasion of pathogenic organisms. Despite the advancements in diagnostic techniques, treatment of pyogenic infections in the developing countries is challenging due to the emergence of multidrug-resistant (MDR) pathogens. This study was done to know the changing pattern of antimicrobial resistance in clinical isolates from pyogenic infections in patients attending a tertiary care hospital at Western Rajasthan, India. Methods and materials: This cross-sectional study was conducted at the Department of Microbiology in a tertiary care hospital during 2014–2015. Clinical specimens such as pus, wound aspirate, sterile body fluids except for CSF, wound swab, necrotic tissue, and surgical drainage were collected aseptically from suspected patients with pyogenic wound infections and processed. Bacterial isolates were identified by standard bacteriological methods and antibiotic susceptibility testing was done by Kirby-Bauer disc diffusion method as per CLSI guidelines. Results: Out of the total of 1190 clinical specimens processed, 231 (19.41%) specimens were from pyogenic infections; 108 (46.75%) specimens were culture positive. Gram-negative pathogens were 34%, followed by gram-positive pathogens which were 23%. Eleven percent were skin commensal flora. S. aureus (23%), E. coli (14%), Klebsiella spp. (7.4%), and Pseudomonas spp. (9.2%) were the common pathogens isolated. Staphylococcus aureus was resistant to Penicillin-G (100%), Erythromycin (56%) followed by Ciprofloxacin (28%). Among Enterobacteriaceae, Escherichia coli and Klebsiella spp. were resistant to Ampicillin (93.75%). and Amoxy-clave (93.75%) followed by ceftriaxone (81.25%). The majority of Pseudomonas isolates were susceptible to most of the antimicrobials. Conclusion: S.aureus and members of enterobacteriaceae are developing more resistance against commonly used antimicrobials, in comparison to Pseudomonas, which is commonly considered as a most resistant pathogen. This changing pattern is important in making the antibiotic policy.

Innovation for a digital world: An evaluation of an open-access antimicrobial resistance surveillance system in tropical Australia

Background: Timely, accurate and accessible antimicrobial susceptibility data are essential for effective clinical and public health responses. In northern Australia, bacterial infection rates are high but resistance to antibiotics is poorly described. HOTspots (amrhotspots.com.au) is a regional, laboratory-based, passive surveillance system that aims to inform clinical management of patients, treatment guidelines and policies. Here we evaluate the utility of this prototype system to end users. Methods and materials: The evaluation was guided by the Centre for Disease Control's framework for evaluating public health surveillance systems. Evidence to assess the system attributes of simplicity, flexibility, acceptability, timeliness, and stability was collected through interviews with clinicians, guideline contributors and policy-makers. Data quality and sensitivity were determined by interviews and an audit of HOTspots data against available antimicrobial susceptibility data. Representativeness was analysed by comparing population coverage of participating and non-participating pathology service providers. Results: The system is simple in structure and operation but could be improved by standardising data collection from laboratories. The data management process facilitates system flexibility, but platform limitations are a barrier to the simplicity, flexibility and acceptability of the system. Acceptability was reduced by the inability to support nuanced clinical and public health decision-making, although enhanced by timely data provision. Future challenges to stability include sustainable governance, funding and human resourcing. Data completeness was high and validity good, though could be improved through quality assurance. The system was found to be sensitive, with an average 94.9% agreement between HOTspots data and local susceptibility data. Three major pathology service providers, who service public and private, hospital and community populations, have contributed data, establishing high quality representativeness of the system. Conclusion: HOTspots’ strength lies in its provision of timely, representative and accurate antimicrobial susceptibility data to end users in northern Australia. Recommendations to enhance the system include standardising data collection, upgrading the platform and working with end users to build more nuanced clinical and public health decision-making support. Sustainable governance and resourcing are essential to achieving this aim. Successful implementation of HOTspots into regional surveillance activities will innovate the way health services receive and act on changing patterns of antimicrobial resistance.

Streptococcus agalactiae macrolide/lincosamide resistance; implications for puerperal antimicrobial therapy

Introduction There is no routine screening for antenatal Group B Streptococcus (GBS) carriage in the UK. However where GBS is identified from clinical urine/vaginal samples, peri-partum antimicrobial therapy is advised. The changing pattern of antimicrobial resistance among GBS, particularly for macrolides/lincosamides, has implications for peri-partum antimicrobial for beta-lactam allergic patients. Method We undertook a retrospective observational study at a central London teaching hospital to investigate GBS antimicrobial resistance and peri-partum prescribing between 1st April 2016 and 31st March 2019. Results 939 obstetric patients had GBS identified at Chelsea & Westminster Hospital during the study period. 31% (279(263 resistant and 16 intermediate)/900) were erythromycin resistant and 27% (246/911) clindamycin resistant. 5.6% (51/900) had incongruent erythromycin/clindamycin resistance, presumed erm mediated. 390 women received peri-partum antimicrobials for GBS. The majority of patients received benzylpenicillin therapy (70.2%, 274/390), with cefuroxime (23.1%, 90/390), clindamycin (5.6%,22/390) and teicoplanin (1%,4/390) based therapies also used. 40.9% (9/22) were given clindamycin despite known GBS resistance. Conclusion Our data support the national guidelines, with high erythromycin/clindamycin resistance reported locally. Updated UK guidelines for GBS colonised patients recommend the use of vancomycin for beta-lactam allergic patients. Yet where sensitivities are known, clindamycin may still be used for 70% of beta-lactam allergic patients. Vancomycin, more challenging to administer and monitor, can be reserved for beta-lactam allergic, clindamycin resistant GBS carriers which account for a minority of the population (2.8%). Developing a working pathway implementation is challenging as evident with the inappropriate clindamycin use in 9 patients locally.

The changing patterns of antimicrobial resistance in E. coli urine and blood isolates in the community and nosocomial populations of East Suffolk (UK), 2009-2016

The changing patterns of antimicrobial resistance in E. coli urine and blood isolates in the community and nosocomial populations of East Suffolk (UK), 2009-2016

Microbiology and antimicrobial susceptibility of otitis externa: a changing pattern of antimicrobial resistance.

Otitis externa is a common presentation to secondary care otolaryngology clinics. Despite this, few studies have investigated the microbiology and antimicrobial resistance of otitis externa. This study aimed to examine these issues. Analysis identified 302 swabs taken from 217 patients (100 male, 117 female), between 1 January 2015 and 30 March 2016, at our rapid access otolaryngology clinic. In total, 315 organisms were isolated; the most frequent was Pseudomonas aeruginosa (31.1 per cent), followed by candida species (22.9 per cent) and Staphylococcus aureus (11.7 per cent). P aeruginosa was sensitive to ciprofloxacin in 97.7 per cent of cases and to gentamicin in 78.4 per cent. Compared with studies worldwide, the relative proportions of different organisms causing otitis externa and the patterns of antimicrobial resistance differ. Increasing resistance of P aeruginosa to aminoglycosides demonstrates a changing pattern of antimicrobial resistance that has not been previously reported. Reassuringly, quinolone antibiotics remain highly effective when treating P aeruginosa.

Spectrum of constitutive and inducible clindamycin resistance in Staphylococcus spp isolated from clinical samples and its relation with methicillin resistance.

Backgound: Increasing Staphylococcal infections with changing patterns of antimicrobial resistance has led to renewed interest in macrolide-lincosamide-streptogramin group B (MLS B ) antibiotic. Misuse of MLS B antibiotics has increased resistance of Staphylococcusspp. to these drugs. Failure to detect inducible clindamycin resistance leads to therapeutic failure. Determine the prevalence of constitutive and inducible clindamycin resistance in clinical isolates of Staphylococcus spp. Ascertain the relationship between methicillin-resistance in Staphylococcus spp with constitutive and inducible clindamycin resistance. Methods: Prospective study was carried over a period of six months with 722 clinical specimens. A total of 184 Staphylococcal isolates were identified. Staphylococcal isolates were speciated as S aureus, S epidermidis and S saprophyticus. Antibiotic susceptibility testing was done by Kirby-Bauer’s disc diffusion method using cefoxitin, erythromycin, and clindamycin. A disc approximation test was performed for detection of inducible clindamycin resistance for all strains resistant to erythromycin but sensitive to clindamycin. Results: Out of 184 staphylococcal isolates, 128 (69.5%) S aureus and 56 (30.4%) Coagulase negative Staphylococcus spp were identified. 114 (61.9%) of the isolates were susceptible to both clindamycin and erythromycin. Overall 70 (38.04%) isolates were resistant to erythromycin. Out of these,38 (54.2%%) of strains depicted cMLS B phenotype being resistant to both erythromycin and clindamycin.20 (28.5%) isolates showed inducible clindamycin resistance while 12(17.1%) isolates indicated MS phenotype. Percentage of both constitutive and inducible clindamycin resistance was found to be higher in methicillin resistant staphylococcal isolates than methicillin sensitive isolates. Conclusions: We recommend that the clinical microbiology laboratories should test the isolates for inducible clindamycin resistance by D test, for all isolates that appear erythromycin resistant and clindamycin susceptible in vitro.

Inducible Clindamycin Resistance in Clinical Isolates of Staphylococci

Background: The increasing frequency of methicillin-resistant Staphylococcus aureus (MRSA) infections and the changing patterns of antimicrobial resistance have led to renewed interest in the use of macrolide-lincosamide – streptogramin B (MLSB) antibiotics to treat such infections. However, resistance to MLSB antibiotics has been reported to be mediated by the msrA gene coding for efflux mechanism and erm gene which encoding the enzymes conferring resistance to MLSB antibiotics. Routine antibiotic sensitivity tests for clindamycin may fail to detect inducible clindamycin resistance due to the presence of the erm gene thereby resulting in failure of treatment. Aim: This study was undertaken to detect the presence of inducible clindamycin resistance among clinical isolates of staphylococci. Materials and Methods: A total of 247 strains of staphylococci (S. aureus - 158 and coagulase-negative staphylococci (CoNS) – 89), isolated from various clinical samples were included in this study. The isolates were identified using conventional methods. Inducible clindamycin resistance was tested by D test as per the CLSI guidelines. Results: Of total 247 isolates included in this study 52(21.05%) were MRSA, 67(27.13%) were Methicillin Resistant Coagulase Negative Staphylococci (MR-CoNS). Inducible clindamycin resistance was detected in 13.46 % of 52 MRSA and 2.99% of 67 MR-CoNS. Conclusion: Staphylococcal isolates, particularly MRSA, must be tested routinely by the D-test before treatment so that the clindamycin drug is used effectively and for maximum clinical utility.

English

Escherichia coli is an important cause of both community acquired (CA) and hospital acquired (HA) bacteremia. A prospective study was conducted at a tertiary care University Hospital from January, 2012 to July 2014, to compare the clinical features, risk factors, outcomes and antimicrobial resistance between E. coli bacteremia acquired from the community (CA) versus E. coli bacteremia acquired from the hospital (HA). Clinical and laboratory data of 171 adult patients with at least one positive blood culture of E. coli were analyzed. Data were collected from patients with significant blood stream infection, using medical and laboratory record files and information from treating medical staff. The overall incidence of extended spectrum beta lactamase (ESBL) infection was high, 67/171 (77.4%). Thirty-eight (40.9%) of the CA isolates were found to produce ESBL, while 28 (35.9%) of the HA isolates were ESBL producers. Patients with CA bacteremia tend to be older than those with HA bacteremia (0.003). Neoplastic diseases (hematological malignancy (<0.001), solid tumors (<0.001)), renal transplantation end stage renal disease (ESRD) (<0.006), and wound infection (<0.001) were the most commonly associated conditions in patients with HA bacteremia. Patients from the community are more likely to present with UTI (<0.001), fever and pyelonephritis (0.001). Both CA and HA E. coli isolates showed the highest sensitivity to imipenem, meropenem and amikacin followed by gentamicin and tazocin. The CA isolates are more susceptible to amikacin, tazocin and ciprofloxacin than the HA isolates. No significant difference in the mortality rate between patients with CA bacteremia and patients who acquire the bacteremia in a hospital setting (0.836) was observed. Clinicians need to be aware of the risk factors and changing pattern of antimicrobial resistance of this pathogen and should consider adequate empirical therapy with coverage of these pathogens for patients with risk factors Key words: Escherichia coli, community acquired, hospital acquired, bacteremia, blood stream infection.

A retrospective study of the changing trends of antimicrobial resistance of Klebsiella pneumoniae isolated from urine samples over last 3 years (2012-2014).

Background:In our country, the problem of antibiotic resistance is compounding because of overuse and misuse of antibiotics. There is no systematic national surveillance of antibiotic resistance and insufficient data are available to quantify the problem.Objectives:To study the changing pattern of antimicrobial resistance of Klebsiella pneumoniae isolates from patients of urinary tract infections over last 3 years.Materials and Methods:A retrospective, record-based study carried out based on the records culture sensitivity reports of indoor patients, during past 3 years (2012-2014). The type of organisms most common in urine sample was noted, and the drugs still effective for the particular organism were noted.Results:Klebsiella was the second most frequent isolate throughout the 3 years (14%) of the total isolates). Analysis of the results year wise indicated that the lowest percentage of resistance was manifested against imipenem between 11.94% (2012) and 13.75% (2014). Over the successive years, resistance to ceftriaxone tends to increase from 74.95 % (2012) to 81% (2014). Klebsiella showed very high resistance 90.78% (2012) and 95.63% (2012) to co-trimoxazole and tetracycline, respectively with increasing trend to absolute resistance to both groups over the 3 years period. On an average over the 3 years Klebsiella showed a high amount of resistances to fluoroquinolones (72.71%) and aminoglycosides (76.22%). While multi-drug resistant Klebsiella range between 65% (2012) and 67% (2014).Conclusion:The antimicrobial resistance patterns are constantly evolving and vary from region to region it has become a necessity to do constant antimicrobial sensitivity surveillance. This will help clinicians to provide safe and effective empirical therapies.

A retrospective study of antimicrobial resistance pattern of Pseudomonas aeruginosa isolates from urine samples over last three years (2013-2015)

Background: Problem of antibiotic resistance is compounding day by day because of overuse and misuse of antibiotics. There is no systematic national surveillance of antibiotic resistance and insufficient data is available to quantify the problem in our country. This study aims at studying the changing pattern of antimicrobial resistance of Pseudomonas aeruginosa isolates from patients of urinary tract infections over last three years. Methods: A retrospective, record based study carried out based on the records of C/S (Culture sensitivity) reports of indoor patients, during past three years (2013 - 2015). The types of organisms causing urinary tract infections were noted and the drugs still effective for the Pseudomonas aeruginosa were noted. Results: Pseudomonas aeruginosa is inherently resistant to many antimicrobial agents. Analysis of the results year wise indicated that the lowest percentage of resistance manifested against imipenem was 14%, 24.48% and 20.99% for the years 2013-2015. Resistance for fluoroquinolones decreased over the three consective years from 84.67% (2013) to 78.27% (2015). Over the successive years, the resistance to ceftriaxone tends to increase from 80% (2013) to 92.59% (2015). C/S reports showed on an average 69% were resistant to aminoglycosides. Multi drug resistant pseudomonas percentage resistant to fluoroquinolones, third generation cephalosporines and aminoglycosides were 78% (2013), 78.33% and 80.33% (2015) over the consective years. Conclusions: The antimicrobial resistance patterns are constantly evolving and vary from region to region it has become a necessity to do constant antimicrobial sensitivity surveillance. This will help clinicians to provide safe and effective empirical therapies.

Pattern Of Antimicrobial Resistance Of Escherichia Coli Isolates From Urinary Tract Infection Patients: A Three Year Retrospective Study

ABSTRACT Objectives: To study the changing pattern of antimicrobial resistance of Escherichia coli isolates from patients of urinary tract infections over last three years Materials and Methods: A retrospective , record based study carried out based on the records of Culture sensitivity (C/S)reports of indoor patients, during past three years (2012 - 2014). The type of organisms most common in urine sample was noted and the drugs still effective for the particular organism were noted . Results: E.coli was the most frequent isolate throughout the three years (67.66% of the total isolates). Analysis of the results year wise indicated that ¬¬¬ the lowest percentage of resistance was manifested against imipenem between 11.86%(2012)to11.36%(2014) .Resistance for nitrofurantoin decreased over the three consective years from 36.1%(2012) to 18.15%(2014). Over the successive years, resistance to ceftriaxone tends to increase from 53.39 %(2012) to 73.33%(2014). E coli showed absolute resistance (100%) to cotrimoxazole and tetracycline . On an average over the three years E.coli showed high amount of resistances to fluoroquinolones (75%) and aminoglycosides(67%) .While Multi drug resistant (MDR) E.coli range between 63%(2012) to 65%(2014) . Conclusion: The antimicrobial resistance patterns are constantly evolving and vary from region to region it has become a necessity to do a constant antimicrobial sensitivity surveillance. This will help clinicians to provide safe and effective empirical therapies.

Comparison of the Antibiotic Resistance ofHelicobacter pyloriIsolated in Jinju Over a 15-year Period

The aims of this study were to investigate the changing pattern of Helicobacter pylori antibiotic resistance in Jinju over a 15-year period. H. pylori strains were isolated from 170 adults living in Jinju from 1985-1989, 1990-1994 and 1995-1999, and from 23 adults living in Cheongju from 1995 to 1999. Susceptibility to erythromycin, clarithromycin, azithromycin, amoxicillin, tetracycline, metronidazole, furazolidone, levofloxacin, ciprofloxacin, moxifloxacin, and rifabutin was tested using the serial two-fold agar dilution method. Moxifloxacin resistance significantly increased in Jinju from 1985-1989 (0%) to 1995-1999 (14.9%) (p < 0.0001). Resistance to amoxicillin was increasesed trend to decreased trend from 1985 to 1999 (p = 0.033), whereas metronidazole resistance decreased from 37.5% to 21.3%. Resistance to furazolidone was greater from 1985-1989 (9.4%) than in 1995-1999 (2.1%). In comparing Jinju and Cheongju, minimal inhibitory concentrations (MICs) of tetracycline and levofloxacin among H. pylori isolated from Jinju were lower than for isolates from Cheonju (p < 0.05). The levofloxacin resistance rate was higher in Cheongju than in Jinju (p = 0.02). No macrolide resistance was observed in Cheongju. Overall, we did not observe any remarkable antimicrobial resistance increase of H. pylori strains isolated from Jinju over 15 years. The MIC distributions of antimicrobials and antimicrobial resistant rates were time- and region-specific among different strains. Future anti-H. pylori eradication regimens should be designed based on the changing patterns of antimicrobial resistance according to the resident area.

The changing pattern of antimicrobial resistance within 42 033 Escherichia coli isolates from nosocomial, community and urology patient‐specific urinary tract infections, Dublin, 1999–2009

To investigate the changing pattern of antimicrobial resistance in Escherichia coli urinary tract infection over an eleven year period, and to determine whether E. coli antibiotic resistance rates vary depending on whether the UTI represents a nosocomial, community acquired or urology patient specific infection. A retrospective analysis of the 42,033 E. coli urine isolates from the 11-year period 1999-2009 in a single Dublin teaching hospital was performed. WHONET(TM) software was used to analyse the changing pattern of sensitivity and resistance of E. coli to commonly used antibiotics over the study period. The origins of the urine samples were stratified into three groups: inpatients with nosocomial UTIs; urine originating from the emergency department and general practice (community UTIs); and UTIs in urology patients. Urinary tract infections in the urology patient population demonstrate higher antibiotic resistance rates than nosocomial or community UTIs. There were significant trends of increasing resistance over the 11-year period for ampicillin, trimethoprim, gentamicin and ciprofloxacin, and significant differences in co-amoxyclav, gentamicin, nitrofurantion and ciprofloxacin resistance rates depending on the sample origin. Ampicillin and trimethoprim were the least active agents against E. coli, with total 11-year resistance rates of 58.3 and 33.8%, respectively. The overall gentamicin resistance rate was 3.4% and is climbing at a rate of 0.7% per year (P < 0.001). Within the urology patient population the resistance rate was 6.4%. Ciprofloxacin resistance approaches 20% in the nosocomial UTI population and approaches 30% in the urology population; however, it remains a reasonable empirical antibiotic choice in this community, with an 11-year resistance rate of 10.6%. E. coli remains the commonest infecting uropathogen in the community and hospital setting with its incidence climbing from 50 to 60% of UTIs over the 11-year period. Neither penicillins nor trimethoprim represent suitable empirical antimicrobials for UTI and ciprofloxacin resistance in this Dublin-based study renders it unsuitable empirical therapy for nosocomial UTIs and UTIs in the urology population. The dramatic 11-year rate increase in gentamicin resistance is of paramount concern.

Mucoid Pseudomonads in Patients With Noncystic Fibrosis Bronchiectasis

To the Editor: Mucoid Pseudomonas aeruginosa is isolated in up to 40% of noncystic fibrosis patients with chronic bronchitis and other obstructive lung diseases.1 Apart from P. aeruginosa, mucoid strains of other species of pseudomonads are infrequently discussed; and in most of the laboratories that lack automated systems, their identification is not attempted and is reported as "Pseudomonas species not aeruginosa." Mucoid pseudomonads are lung colonizers in patients with bronchiectasis and frequently cause secondary infections leading to increased mortality and morbidity.2 In this study, we have characterized and determined the antimicrobial susceptibility of mucoid pseudomonads strains, isolated from sputum of adult patients with noncystic fibrosis bronchiectasis using simple biochemical tests, which are routinely available in a microbiology laboratory. Antimicrobial susceptibility testing and metallo-β-lactamase production were done using standard methods.3 A total of 97 strains were isolated from 871 sputum samples during the study period. Among them, P. aeruginosa (n = 49, 50.5%) was the commonest isolate, followed by Pseudomonas fluorescens (n = 15), Pseudomonas putida (n = 8), Pseudomonas pseudoalcaligenes (n = 5), Brevundimonas vesicularis (n = 5), CDC group Vb-3 (n = 4), Pseudomonas spp group 1(n = 3), Pseudomonas mendocina (n = 2), Burkholderia cepacia complex (n = 2), Ralstonia pickettii (n = 2), Pseudomonas luteola (n = 1), and Brevundimonas diminuta (n = 1). Antimicrobial susceptibility pattern showed that majority of isolates were multidrug resistant, and polymyxin B was found to be most effective antibiotic. Metallo-β-lactamase production was determined in 19 meropenem resistant strains, and 12 (63%) of 19 isolates were metallo-β-lactamase positive (Table 1).TABLE 1: Antimicrobial Susceptibility Pattern of the Common Mucoid Pseudomonads IsolatesAmong pseudomonads, P. aeruginosa is the most common human pathogen. The first report of mucoid P. aeruginosa isolation came in 1927 from a patient with a fistulating abscess of the gallbladder.2 In the first detailed study, Elston and Hoffman4 reported an incidence of mucoid forms as 1.7%, and Fujita et al5 were the first worker to report mucoid P. putida causing pulmonary infection in an immunocompetent host. Generally, "Pseudomonas non-aeruginosa" species are considered as environment contaminant; however, results of this study indicate that Pseudomonas non-aeruginosa constituted 49.5% of mucoid pseudomonal isolates in patients with bronchiectasis and are an emerging cause of respiratory infections in patients with bronchiectasis. Antimicrobial resistance among them is of increasing concern as not only P. aeruginosa but also other pseudomonads were also found to be multidrug resistant, and these probably demonstrate the changing pattern of antimicrobial resistance in pseudomonads. Further large-scale studies are required to look for epidemiological distribution of mucoid strains and study their antimicrobial susceptibility pattern. Atul Garg, MD, DNB S. Sujatha, MD Jaya Garg, MD, DNB Nasreen H., MSc S. C. Parija, MD, FRCPath Department of Microbiology Jawaharlal Institute of Postgraduate Medical Education and Research Pondicherry, India [email protected]

Antibiotic resistance of urinary tract pathogens and evaluation of empirical treatment in Turkish children with urinary tract infections

The changing pattern of antimicrobial resistance in the causative microorganisms of urinary tract infection (UTI) in childhood is a growing problem. The aims of this study were to assess the resistance patterns of urinary isolates to commonly used antimicrobials and to evaluate the options for empirical treatment of UTI. A prospective cross-sectional analysis of bacteria isolated from children with UTI was performed between January 2003 and January 2004. Resistance to antibiotics was analysed in three age groups: Group I, ≤12 months; Group II, 13–60 months; and Group III, >60 months. A total of 165 urinary pathogens were isolated from 131 patients. Mean patient age was 63.7 ± 49.8 months. The most common causative agent was Escherichia coli (87% of cases) followed by Klebsiella pneumoniae (10%). Resistance to ampicillin (74.2%) and co-trimoxazole (61.3%) was significant in all isolates. Nitrofurantoin was the most active agent against E. coli (2.2% resistant isolates), followed by amikacin (4.9%), ceftriaxone (7.5%) and ciprofloxacin (12%). None of the isolates from Group I patients were resistant to ciprofloxacin and a low resistance rate (7.1%) was noted for amikacin. In Group II patients, none of the isolates were resistant to amikacin, and ceftriaxone was the second most suitable antibiotic (resistance rate 2.2%). In Group III patients, the lowest resistance rate was against nitrofurantoin (2.7%). In conclusion, we observed that the use of ampicillin and co-trimoxazole as a single agent for empirical treatment of a suspected UTI would not cover the majority of urinary pathogens in our region. Whilst amikacin, with a negligible resistance rate, was suitable in all age groups, gentamicin might still be useful as an empirical treatment of UTI in children aged >1 year. Nitrofurantoin could be included as a reasonable alternative in the empirical treatment of lower UTI in older children.

Antimicrobial drug resistance in Salmonella enterica.

This review addresses the changing patterns of antimicrobial resistance in Salmonella. Resistance to chloramphenicol, amicillin and cotrimoxazole is common in Salmonella Typhi and Paratyphi A in Asia and a few countries of Africa. In some countries, the isolation of multidrug resistant strains appears to be declining. R-type ACSSuT Salmonella Typhimurium DT104 is common in animal and human infections in many industrialized countries. Strains with additional trimethoprim and low-level ciprofloxacin resistance are increasingly seen. Resistance is appearing in new Typhimurium phage types, such as DT204b, and is common in serotypes Hadar and Virchow but not Enteritidis. A variety of Ambler class A and class C beta-lactamase enzymes have now been described causing extended spectrum cephalosporin resistance in different Salmonella serotypes. The overall level of extended spectrum cephalosporin resistance currently appears low. Low-level ciprofloxacin resistance, associated with point mutations in the gyrA gene, is inceasingly common in typhoidal and non-typhoidal serotypes isolated from humans and animals and has been associated with treatment failures. Sporadic reports describe human infections with non-Typhi Salmonella that are fully fluoroquinolone resistant. There is increasing support for the call to revise the fluoroquinolone breakpoints for Salmonella. A study from Denmark suggested that infections with drug resistant Salmonellae are associated with a poorer outcome than drug susceptible infections. Resistance is increasing to several critical antimicrobials used to treat invasive salmonellosis including extended spectrum cephalosporins and quinolones. In resource poor countries, such drug resistant Salmonella infections may become effectively untreatable.

Plasmid-mediated resistance of Neisseria gonorrhoeae strains isolated from female sex workers in North Sumatra, Indonesia, 1996.

Sentinel surveillance of the antimicrobial resistance of strains isolated from female sex workers in North Sumatra, Indonesia, has been carried out since 1975. In 1996 a high prevalence of strains with plasmid-mediated resistance to tetracycline and penicillin was observed. The goal was to further characterize strains isolated from a core group of patients in Indonesia with sexually transmitted infections in 1996. The strains were characterized by antimicrobial susceptibility testing, plasmid analysis, subtype of the determinant, and analysis of genomic DNA by pulsed-field gel electrophoresis (PFGE). A total 161 strains obtained from 592 female sex workers in 10 different places in North Sumatra, Indonesia, in 1996 were investigated. All strains exhibited plasmid-mediated resistance to penicillin (PPNG: penicillinase-producing ) and/or tetracycline (TRNG: tetracycline-resistant ); 115 strains were PPNG/TRNG (71%), 45 were TRNG (28%), and 1 was PPNG. All strains were susceptible to ceftriaxone, ciprofloxacin, kanamycin, and spectinomycin. All PPNG strains tested carried the 7.2-kb (Asian type) plasmid except one, which carried the 4.9-kb (Toronto type) plasmid. All TRNG strains except one contained the Dutch-type gene. PFGE analysis of 156 strains documented that a diversity of strains existed and that certain genotypes had spread in a defined area or between different areas in North Sumatra. Our results underline the importance of continuous surveillance of the changing patterns of antimicrobial resistance of in high-risk populations.

Antimicrobial resistance in Neisseria gonorrhoeae.

The changing patterns of antimicrobial resistance in Neisseria gonorrhoeae have been reviewed regularly since the introduction of antimicrobial therapy in the 1930s. At present, ceftriaxone, fluoroquinolones, and spectinomycin have remained efficient as single-dose treatment of gonorrhea worldwide. To ensure that limited resources can be used in the best possible way, continuous surveillance of gonococcal resistance to antimicrobials is needed.