Trimethoprim-sulfamethoxazole Resistance Research Articles

Dissemination of Trimethoprim–Sulfamethoxazole Drug Resistance Genes Associated with Class 1 and Class 2 Integrons Among Gram-Negative Bacteria from HIV Patients in South India

The antibiotic, trimethoprim-sulfamethoxazole (TMP-SMX), is generally used for prophylaxis in HIV individuals to protect them from Pneumocystis jiroveci infection. Long-term use of TMP-SMX develops drug resistance among bacteria in HIV patients. The study was aimed to detect the TMP-SMX resistance genes among gram-negative bacteria from HIV patients. TMP-SMX-resistant isolates were detected by the Kirby-Bauer disc diffusion method. While TMP resistance genes such as dfrA1, dfrA5, dfrA7, and dfrA17 and SMX resistance genes such as sul1 and sul2 were detected by multiplex PCR, class 1 and class 2 integrons were detected by standard monoplex PCR. Of the 151 TMP-SMX-resistant bacterial isolates, 3 were positive for sul1 alone, 48 for sul2 alone, 11 for dfrA7 alone, 21 for sul1 and sul2, 1 for sul1 and dfrA7, 23 for sul2 and dfrA7, 2 for sul2 and dfrA5, 41 for sul1, sul2, and dfrA7, and 1 for sul2, dfrA5, and dfrA7. Of 60 TMP-SMX-resistant isolates positive for integrons, 44 had class 1 and 16 had class 2 integrons. It was found that the prevalence of sul genes (n = 202; p < 0.001) was higher compared with dfr genes (n = 80; p < 0.001), and 87.4% (n = 132; p < 0.001) of TMP-SMX-resistant isolates also were positive for β-lactamase production. This type of study is reported for the first time from HIV patients in India. Therefore, this study indicates that dissemination of TMP-SMX resistance genes and class 1 and class 2 integrons along with β-lactamase production among gram-negative bacteria in HIV patients will certainly make their treatment to bacterial infections more complicated in clinical settings.

Surveillance of Dihydropteroate Synthase Genes in Stenotrophomonas maltophilia by LAMP: Implications for Infection Control and Initial Therapy.

Stenotrophomonas maltophilia is a common nosocomial pathogen that causes high morbidity and mortality. Because of its inherent extended antibiotic resistance, therapeutic options for S. maltophilia are limited, and sulfamethoxazole/trimethoprim (SXT) is the only first-line antimicrobial recommended. However, with the spread of dihydropteroate synthase (sul1 and sul2) genes, global emergence of SXT resistance has been reported. There is an urgent need to develop a rapid and sensitive but cost-efficient method to monitor the dissemination of sul genes. In this study, we developed loop-mediated isothermal amplification (LAMP) assays for sul1 and sul2 using real-time turbidity and hydroxy naphthol blue coloration methods. The assays could quickly detect sul genes with high sensitivity and specificity. The LAMP detection limit was 0.74 pg/reaction of extracted genomic DNA for sul1 and 2.6 pg/reaction for sul2, which were both 10-fold more sensitive than the corresponding traditional PCR assays. Additionally, the LAMP assays could positively amplify DNA from sul1-producing strains, but not from the negative controls. We then used the LAMP assays to investigate the dissemination of sul genes among S. maltophilia isolates from patients in three hospitals in Beijing, China. Among 450 non-duplicated samples collected during 2012–2014, 56 (12.4%) strains were SXT-resistant. All these SXT-resistant strains were positive for sul genes, with 35 (62.5%) carrying sul1, 17 (30.4%) carrying sul2, and 4 (7.1%) carrying both sul1 and sul2, which indicated that sul genes were the predominant resistance mechanism. Of 394 SXT-susceptible strains, 16 were also sul-positive. To provide epidemiological data for the appropriate choice of antimicrobials for treatment of sul-positive S. maltophilia, we further tested the susceptibility to 18 antimicrobials. Among these, sul-positive strains showed the highest susceptibility to tetracycline derivatives, especially minocycline (MIC50/MIC90, 0.5/4; susceptibility rate, 95.4%). Ticarcillin-clavulanate and new fluoroquinolones (moxifloxacin and levofloxacin) also showed some in vitro activity. Apart from these three kinds of antimicrobials, other agents showed poor activity against sul-positive strains.

Streptococcus pneumoniae Serotypes 9 and 14 Circulating in Brazil over a 23-Year Period Prior to Introduction of the 10-Valent Pneumococcal Conjugate Vaccine: Role of International Clones in the Evolution of Antimicrobial Resistance and Description of a Novel Genotype

Antimicrobial-resistant pneumococcal strains have been detected worldwide since the 1960s. In Brazil, the first penicillin-nonsusceptible pneumococci (PNSP) were reported in the 1980s, and their emergence and dissemination have been mainly attributed to serogroup 9 and serotype 14 strains, especially those highly related to recognized international clones. In the present study, antimicrobial susceptibility testing and multilocus sequence typing were performed on 315 pneumococcal isolates belonging to serogroup 9 (n = 99) or serotype 14 (n = 216), recovered from patients or asymptomatic carriers between 1988 and 2011 in Brazil, in order to trace changes in antimicrobial resistance and genotypes prior to the full introduction of the pneumococcal conjugate vaccine in the country. Over the 23-year study period, the PNSP levels increased, and four clonal complexes (CC156, CC66, CC15, and CC5401) have played important roles in the evolution and dissemination of pneumococcal isolates belonging to serogroup 9 and serotype 14, as well as in the emergence of antimicrobial resistance, in the pre-pneumococcal-vaccination era. The earliest PNSP strains detected in this study belonged to serotype 9N/ST66 and were single locus variants of the international clone Tennessee14-18 ST67 (CC66). The first serotype 14 PNSP isolates were identified in 1990 and were related to the England14-9 ST9 (CC15) clone. Serotype 14 PNSP variants of the Spain9V-3 ST156 clone with elevated penicillin MICs and nonsusceptibility to other beta-lactams were detected in 1995 and showed an increasing trend over the years. The results also indicated that introduction of ST156 in our region was preceded by the emergence of trimethoprim-sulfamethoxazole resistance and by the dissemination of ST162. In addition to the presence of successful international clones, a novel regional serotype 14 genotype (CC5401) has emerged in 1996.

EFFECT OF TRIMETHOPRIM-SULFAMETHOXAZOLE PROPHYLAXIS ON FAECAL CARRIAGE RATES OF RESISTANT ISOLATES OF ESCHERICHIA COLI IN HIV-INFECTED ADULT PATIENTS IN LAGOS.

Background:The daily use of Trimethoprim-Sulfamethoxazole (TMP-SMX) prophylaxis reduces morbidity and mortality among patients infected with Human Immunodeficiency Virus (HIV) but its impact on increasing antimicrobial resistance rates has been of public concern globally. This study investigated the effect of daily TMP-SMX prophylaxis on faecal carriage rates of resistant isolates of Escherichia coli in HIV-infected adult patients in Lagos.Methods:A total of 550 HIV-infected patients with CD4-cell count of less than 350 cell/mm3 and were eligible for TMP-SMX prophylaxis attending Lagos University Teaching Hospital, Lagos, Nigeria, were recruited. Stool/rectal swab samples were aseptically collected from the patients and processed using standard methods for culture and sensitivity.Results:There was a baseline Trimethoprim-Sulfamethoxazole resistance rate of 54% which increased to 77.9% in first 3 months, rising to 96.1% by 6 months and all isolates were resistant by the 9th month. There was also evidence of cross-resistance to other antibiotics with significant association with TMP-SMX resistance (p<0.0001). The Escherichia coli isolates showed a progressive increase in resistance to the tested antibiotics over the 12-month period. The resistance was in the following order: Ampicillin (74% to 82.6% in the first 3 months; 98.3% by the 6th month and 99.4% by the 9th month; all isolates were resistant by the 12th month). Augmentin (32.5% to 47.7% in first 3 months; 76.1% by the 6th month; 86.3% by the 9th month; all isolates were resistant by 12 months). Ceftriaxone (2.0% to 10.8% in first 3 months; 20.6% by the 6th month; 24.2% by the 9th month; 54.3% by the 12 months).Conclusion:The carriage rate of faecal E. coli resistant to TMP-SMX is common before TMP-SMX prophylaxis. Initiation of TMP-SMX leads to further increase in resistance to TMP-SMX and cross-resistance to other antimicrobials.

Antimicrobial Resistance and Urinary Tract Infection Recurrence.

The Randomized Intervention for Children with Vesicoureteral Reflux (RIVUR) trial found that recurrent urinary tract infections (rUTI) with resistant organisms were more common in the trimethoprim-sulfamethoxazole prophylaxis (TSP) arm. We describe factors associated with trimethoprim-sulfamethoxazole (TMP-SMX) resistance of rUTIs in RIVUR. Children aged 2 to 71 months with first or second UTI (index UTI) and grade I to IV vesicoureteral reflux (VUR) were randomized to TSP or placebo and followed for 2 years. Factors associated with TMP-SMX-resistant rUTI were evaluated. Among 571 included children, 48% were <12 months old, 43% had grade II VUR, and 38% had grade III VUR. Recurrent UTI occurred in 34 of 278 children receiving TSP versus 67 of 293 children receiving placebo. Among those with rUTI, 76% (26/34) of subjects receiving TSP had TMP-SMX-resistant organisms versus 28% (19/67) of subjects receiving placebo (P < .001). The proportion of TMP-SMX-resistant rUTI decreased over time: in the TSP arm, 96% were resistant during the initial 6 months versus 38% resistant during the final 6 months; corresponding proportions for the placebo arm were 32% and 11%. Among children receiving TSP, 7 (13%) of 55 with TMP-SMX-resistant index UTI had rUTI, whereas 27 (12%) of 223 with TMP-SMX-susceptible index UTI had rUTI (adjusted hazard ratio 1.38, 95% confidence interval 0.54-3.56). Corresponding proportions in placebo arm were 17 (26%) of 65 and 50 (22%) of 228 (adjusted hazard ratio 1.33, 95% confidence interval 0.74-2.38). Although TMP-SMX resistance is more common among children treated with TSP versus placebo, resistance decreased over time. Among children treated with TSP, there was no significant difference in UTI recurrence between those with TMP-SMX-resistant index UTI versus TMP-SMX-susceptible UTI.

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Multicentre study highlighting clinical relevance of new high-throughput methodologies in molecular epidemiology of Pneumocystis jirovecii pneumonia

Pneumocystis jirovecii causes severe interstitial pneumonia (PcP) in immunosuppressed patients. This multicentre study assessed the distribution frequencies of epidemiologically relevant genetic markers of P. jirovecii in different geographic populations from Portugal, the USA, Spain, Cuba and Mozambique, and the relationship between the molecular data and the geographical and clinical information, based on a multifactorial approach. The high-throughput typing strategy for P. jirovecii characterization consisted of DNA pooling using quantitative real-time PCR followed by multiplex-PCR/single base extension. The frequencies of relevant P. jirovecii single nucleotide polymorphisms (mt85, SOD110, SOD215, DHFR312, DHPS165 and DHPS171) encoded at four loci were estimated in ten DNA pooled samples representing a total of 182 individual samples. Putative multilocus genotypes of P. jirovecii were shown to be clustered due to geographic differences but were also dependent on clinical characteristics of the populations studied. The haplotype DHFR312T/SOD110C/SOD215T was associated with severe AIDS-related PcP and high P. jirovecii burdens. The frequencies of this genetic variant of P. jirovecii were significantly higher in patients with AIDS-related PcP from Portugal and the USA than in the colonized patients from Portugal, and Spain, and children infected with P. jirovecii from Cuba or Mozambique, highlighting the importance of this haplotype, apparently associated with the severity of the disease and specific clinical groups. Patients from the USA and Mozambique showed higher rates of DHPS mutants, which may suggest the circulation of P. jirovecii organisms potentially related with trimethoprim-sulfamethoxazole resistance in those geographical regions. This report assessed the worldwide distribution of P. jirovecii haplotypes and their epidemiological impact in distinct geographic and clinical populations.

İdrar Yolu Enfeksiyonlarinin Ampirik Tedavisinde İlk Seçenek Antimikrobikler Neler Olmalı?

Objectives : The aims of the study were to investigate the distribution and the antibiotic resistance profiles of the microorganisms isolated from outpatients with lower urinary tract infection (UTI) during 2011-2012 period and to determine the most appropriate empirical therapy choices. Materials and Methods : Culture and susceptibility test results of 14.096 urine samples sent from outpatient clinics with presumptive lower UTI diagnosis in the last year (2011-2012) were reviewed. Excluding the duplications, totally 2005 isolates were evaluated. Culture and identification tests were done by conventional/semi-automatic and automatic methods. Antibiotic susceptibility tests were performed by Kirby-Bauer disc diffusion method according to the recommendations of CLSI (Clinical Laboratory Standarts Institute). Results : Enterobacteriaceae spp. were isolated from 82.3% of the urine samples; 1287 (64.2%) Escherichia coli and 238 (11.9%) Klebsiella pneumonia, 67 (3.3%) Pseudomonas aeruginosa was cultivated. Totally 12.9% of the samples yielded Gram-positive bacteria including 55 (2.8%) meticillin resistant coagulase negative staphylococci , 55 (2.8%) Enterococcus faecalis and 49 (2.4%) Streptococcus agalactiae . The extended spectrum beta-lactamase (ESBL) prevalence was 23.2% in E.coli and 25.4% in K.pneumoniae. Among oral antibiotics tested, nitrofurantoin (NF) had the lowest resistance rates for both Gram-positive and Gram-negative isolates with 2.7% and 12.1%, respectively. Ampicillin for Gram-positives and Cefuroxim for Gram-negatives were other oral drugs with the lowest resistance rates with 6.3% and 25.9%, respectively. Conclusion : NF appears as the most effective oral drug for adult outpatients with UTI. Cefuroxim can be considered as the second effective choice because ampicillin-sensitive Gram-positive isolates (except Enterococcus spp ) would also be sensitive to it. NF and trimethoprim- sulfamethoxazole (TMP-SMX) is suggested as first or second choice in UTI treatment in antimicrobial therapy guidelines like Sanford and IDSA. However, TMP-SMX resistance was found 35% in our population; consequently it is not a suitable option for our patients.

Predominance of dfrG as determinant of trimethoprim resistance in imported Staphylococcus aureus

To investigate the global occurrence of trimethoprim–sulfamethoxazole resistance and the genetic mechanisms of trimethoprim resistance, we analysed Staphylococcus aureus from travel-associated skin and soft-tissue infections treated at 13 travel clinics in Europe. Thirty-eight per cent (75/196) were trimethoprim-resistant and 21% (41/196) were resistant to trimethoprim–sulfamethoxazole. Among methicillin-resistant S. aureus, these proportions were 30% (7/23) and 17% (4/23), respectively. DfrG explained 92% (69/75) of all trimethoprim resistance in S. aureus. Travel to South Asia was associated with the highest risk of acquiring trimethoprim–sulfamethoxazole-resistant S. aureus. We conclude that globally dfrG is the predominant determinant of trimethoprim resistance in human S. aureus infection.

Dynamics of serotype 14 Streptococcus pneumoniae population causing acute respiratory infections among children in China (1997-2012).

BackgroundIn the last decade, the Streptococcus pneumoniae population has changed, mainly due to the abuse of antibiotics. The aim of this study was to determine the genetic structure of 144 S. pneumonia serotype 14 isolates collected from children with acute respiratory infections during 1997–2012 in China.MethodsAll isolated pneumococci were tested for their sensitivity to 11 kinds of antibiotics with the E-test method or disc diffusion. The macrolides resistance genes ermB and mefA, as well as the sulfamethoxazole-trimethoprim resistance gene dihydrofolate reductase (DHFR) were detected by polymerase chain reaction (PCR). The sequence types (STs) were analyzed with multilocus sequence typing (MLST).ResultsFrom 1997 to 2012, the percentage of serotype 14 S. pneumonia isolates in the whole isolates increased. All of the 144 serotype 14 S. pneumonia isolates were susceptible to amoxicillin-clavulanic acid, vancomycin and levofloxacin. No penicillin resistant isolate was found, and the intermediate rate was as low as 0.7 %. Erythromycin resistance was confirmed among 143 isolates. The ermB gene was determined in all erythromycin resistant isolates, and the mefA gene was positive additionally in 13 of them. The non-susceptibility rate to the tested cephalosporins increased from 1997–2012. All trimethoprim-resistant isolates contained the Ile100-Leu mutation. Overall, 30 STs were identified, among which ST876 was the most prevalent, followed by ST875. During the study period, the percentage of CC876 increased from 0 % in 1997–2000 to 96.4 % in 2010–2012, whereas CC875 decreased from 84.2 to 0 %. CC876 showed higher non-susceptibility rates to β-lactam antibiotics than CC875.ConclusionThe percentage of serotype 14 S. pneumonia isolates increased over time in China. The increase of resistance to β-lactam antibiotics in this serotype isolates was associated with the spread of CC876.

Prevalence and characterization of Salmonella isolated from chicken meat in Turkey.

This study was conducted in a Turkish province to investigate the presence of Salmonella spp. in 150 chicken meat samples using 2 phenotyping techniques: classic culture technique (CCT) and immunomagnetic separation (IMS). For the confirmation of the isolates at molecular levels, invA gene was detected in these isolates. The presence of invA, class 1 (Cls1) integrons, and integrase (Int1) genes was demonstrated by PCR assay; and the resistance of the isolated Salmonella spp. strains to antibiotics was determined by disk diffusion test. All the cultural and PCR results were evaluated together; Salmonella spp. were detected in a total of 64 (42.66%) chicken meat samples. Contamination rate was higher in carcasses (53.33%, n = 75) than in meat pieces (32%, n = 75). When results of standard culture were compared with IMS technique, IMS (n = 54) showed a clear superiority over the CCT (n = 38). A very high resistance rate (≥ 89.28%) to vancomycin, tetracycline, streptomycin, or nalidixic acid was found. Trimethoprim-sulfamethoxazole resistance was present in 32.14%. Relatively lower incidence of resistance (≤ 8.33%) to gentamicin, chloramphenicol, ampicillin, and ceftriaxone was observed. Concurrent resistance to at least 4 antibiotics was detected in 92.85% of the isolates. Cls1 integrons and Int1 were positive in 80.95% and 95.23% of the isolates, respectively. However, Int1 alone was detected in 15.47% (n = 13). In conclusion, the high prevalence of Salmonella spp. in chicken meat may pose a potential public health risk, and the presence of antibiotic-resistant Salmonella spp. isolate together with Cls1 integron and/or integrase might play an important role in horizontal antibiotic gene transfer.

Distribution of Class 1 Integrons, sul1 and sul2 Genes Among Clinical Isolates of Stenotrophomonas maltophilia from a Tertiary Care Hospital in North India.

Stenotrophomonas maltophilia is an emerging nosocomial pathogen responsible for serious human infections. This study was carried out to determine antibiotic susceptibility, resistance mechanisms (integrons, sul1 and sul2), and genetic relatedness (Enterobacterial Repetitive Intergenic Consensus [ERIC]-PCR) among 106 clinical isolates of S. maltophilia from India. Twenty-four (22.6%) of S. maltophilia isolates exhibited resistance to mainstay antibiotic trimethoprim-sulfamethoxazole (TMP-SMX). Except for 2 isolates which contained both TMP-SMX resistance determinants sul1 and sul2 genes, all other 22 TMP-SMX-resistant isolates carried either sul1 (10 isolates) or sul2 (12 isolates) genes. Class 1 integrons were present in 8.5% (9 out of 106) of S. maltophilia isolates, and only 5 out of these isolates were TMP-SMX resistant and positive for sul1 gene. The same isolates also carried resistance cassettes containing qac/smr gene. Minocycline and levofloxacin exhibited the maximum in vitro activity against S. maltophilia. ERIC-PCR revealed high diversity among S. maltophilia isolates. The present study demonstrated high (22.4%) TMP-SMX resistance in clinical isolates of S. maltophilia from India. TMP-SMX-resistant isolates carried relatively higher percentage of sul2 gene than sul1 gene as against the reported literature. Majority (58.3%) of sul1 gene positive were not associated with class 1 integrase gene.

Prevalence and risk factors for trimethoprim–sulfamethoxazole-resistant Escherichia coli among women with acute uncomplicated urinary tract infection in a developing country

Prospective studies from developing countries that have investigated risk factors for trimethoprim-sulfamethoxazole (TMP-SMX)-resistant Escherichia coli in women with uncomplicated urinary tract infection (UTI) remain scarce. Women with acute uncomplicated UTI were enrolled prospectively. Urine was sent for antimicrobial susceptibility testing. Logistic regression analysis was used to identify risk factors for TMP-SMX resistance. Of 405 participants, 229 (56.5%) had bacteriuria (mean age 31.9 ± 9.5 years). In the previous 12 months, 77 (33.6%) had experienced at least one UTI episode and 106 (46.3%) reported antimicrobial use. The most common uropathogens were E. coli (75.8%) and Staphylococcus saprophyticus (8.9%). For the 179 E. coli, resistance rates were highest for ampicillin (64.3%) and TMP-SMX (41.3%). Resistance to cephalosporins, nitrofurantoin, and fluoroquinolones was much lower compared with the hospital laboratory-based surveillance data. Risk factors for TMP-SMX resistance were UTI in the last 6 months (odds ratio 2.22; p = 0.04) and the number of UTI episodes in the past year (odds ratio 2.06; p = 0.004). The number of UTI episodes (adjusted odds ratio 2.21; p = 0.02) remained significant on multivariate analysis. TMP-SMX resistance was high. Number of previous UTI episodes was associated with increased risk of resistance; prior antimicrobial use was not. Hospital antibiograms should be used with caution when treating uncomplicated UTI.

Characterization of trimethoprim-sulfamethoxazole resistance genes and their relatedness to class 1 integron and insertion sequence common region in gram-negative bacilli.

Trimethoprim-sulfamethoxazole (TMP-SMX) has been used for the treatment of urinary tract infections, but increasing resistance to TMP-SMX has been reported. In this study, we analyzed TMP-SMX resistance genes and their relatedness with integrons and insertion sequence common regions (ISCRs) in uropathogenic gram-negative bacilli. Consecutive nonduplicate TMP-SMX nonsusceptible clinical isolates of E. coli, K. pneumoniae, Acinetobacter spp., and P. aeruginosa were collected from urine. The minimal inhibitory concentration was determined by Etest. TMP-SMX resistance genes (sul and dfr), integrons, and ISCRs were analyzed by PCR and sequencing. A total of 45 E. coli (37.8%), 15 K. pneumoniae (18.5%), 12 Acinetobacter spp. (70.6%), and 9 Pseudomonas aeruginosa (30.0%) isolates were found to be resistant to TMP-SMX. Their MICs were all over 640. In E. coli and K. pneumoniae, sul1 and dfr genes were highly prevalent in relation with integron1. The sul3 gene was detected in E. coli. However, in P. aeruginosa and Acinetobacter spp., only sul1 was prevalent in relation with class 1 integron; however, dfr was not detected and sul2 was less prevalent than in Enterobacteriaceae. ISCR1 and/or ISCR2 were detected in E. coli, K. pneumoniae, and Acinetobacter spp. but the relatedness with TMP-SMX resistance genes was not prominent. ISCR14 was detected in six isolates of E. coli. In conclusion, resistance mechanisms for TMP-SMX were different between Enterobacteriaceae and glucose non-fermenting gram-negative bacilli. Class 1 integron was widely disseminated in uropathogenic gram-negative baciili, so the adoption of prudent use of antimicrobial agents and the establishment of a surveillance system are needed.

Risk Factor Analysis Among Trimethoprim-Sulfamethoxazole Resistant Escherichia coli Isolates

Background: Trimethoprim-sulfamethoxazole (TMP-SMX) can be used for treatment of several infections including respiratory, renal, and gastrointestinal tract infections, skin and wound infections, septicaemia, and other infections caused by sensitive organisms. Objectives: The aim of this study was to evaluate the risk factors for acquisition of TMP-SMX-resistant Escherichia coli strains among hospitalized patients in a teaching hospital of Sanandaj, Iran. Materials and Methods: It was a case-control study on a patient, carrying a TMP-SMX-resistant E. coli strain. The control patient carried a TMP-SMX-sensitive E. coli strain. TMP-SMX resistance was determined using disk diffusion methods. Results: Of 343 isolates, 197 (57.43%) were TMP-SMX-resistant. Using ventilator and catheter were risky for acquisition of TMP-SMX-resistant isolate (odds ratio (OR) = 3.037, 95% CI = 1.60-5.75, P < 0.000; OR = 2.93, 95% CI = 1.15-7.43, P < 0.013, respectively). There was significant correlation between days of staying in ward and TMP-SMX resistance (P < 0.003). Conclusions: The main risk factors associated with TMP-SMX resistance were using of ventilator and catheter and days of staying in ward. There is need for more studies to evaluate the role of the factors to control the spread of drug resistance.

Antibiotic Susceptibility and mecA Frequency in Staphylococcus epidermidis, Isolated From Intensive Care Unit Patients.

Background:Coagulase-negative staphylococci (CoNS), especially Staphylococcus epidermidis, are considered as normal flora of human epithelia and also important opportunistic pathogens for nosocomial infections. S. epidermidis can also act as a reservoir for mecA, responsible for high-level resistance to methicillin and transferring it to S. aureus.Objectives:The aim of this study was to determine the prevalence of S. epidermidis as well as antibiotic susceptibility pattern and mecA prevalence in S. epidermidis isolated from intensive care unit (ICU) patients.Materials and Methods:A cross-sectional study was conducted from September 2010 to September 2011 and 184 coagulase-negative staphylococci were collected from different clinical samples in three hospitals. S. epidermidis was identified by conventional bacteriological tests. Antibiotic susceptibility testing was performed using disk diffusion method. Frequency of mecA was detected by specific PCR.Results:Frequency of S. epidermidis was 34.8%, the most susceptibility was seen to linezolid and vancomycin, and the least susceptibility was seen to tetracycline.Majority of the S. epidermidis isolates carried mecA (92.2%). The most common resistant pattern was trimethoprim-sulfamethoxazole, tetracycline, erythromycin, and methicillin resistance, found in 23.4% of the isolates, followed by resistance to methicillin as the second-most common resistant pattern, observed in 20.3% of the isolates.Conclusions:Frequency of S. epidermidis was significantly lower, compared to other studies. Presence rate of mecA and susceptibility to linezolid and vancomycin did not show significant differences with other investigations, while resistant to trimethoprim-sulfamethoxazole was significantly lower compared to other investigations, and resistance to tetracycline was significantly higher in comparison to other investigations. Presence of methicillin-resistant S. epidermidis in ICU patients, especially in individuals with compromised immune systems, may cause infection and would be more complicated in the case of antibiotic resistance.

Microbiological features of KPC-producing Enterobacter isolates identified in a U.S. hospital system

Microbiological data regarding Klebsiella pneumoniae carbapenemase (KPC)–producing Enterobacter spp. are scarce. In this study, 11 unique KPC-producing Enterobacter isolates were identified among 44 ertapenem-nonsusceptible Enterobacter isolates collected between 2009 and 2013 at a hospital system in Western Pennsylvania. All cases were healthcare-associated and occurred in medically complex patients. While pulsed-field gel electrophoresis showed diverse restriction patterns overall, multilocus sequence typing identified Enterobacter cloacae isolates with sequence types 93 and 171 from 2 hospitals each. The levels of carbapenem minimum inhibitory concentrations were highly variable. All isolates remained susceptible to colistin and tigecycline, and the majority, to amikacin and doxycycline. A blaKPC-carrying IncN plasmid conferring trimethoprim-sulfamethoxazole resistance was identified in 3 of the isolates. Spread of blaKPC in Enterobacter spp. appears to be due to a combination of plasmid-mediated and clonal processes.

Adult and Pediatric Intra-Institutional Trends of Ciprofloxacin Susceptibility in E. coli Positive Urinary Cultures.

Antimicrobial drug resistance in treatment of urinary tract infection (UTI) continues to rise worldwide. To examine contributions of physician prescribing patterns to fluoroquinolone (ciprofloxacin, CP) resistance, we examined Escherichia coli (E. coli) resistance patterns in urinary cultures. Since CP usage is limited in children, we compared CP resistance trends in adults and children to those of more commonly used trimethoprim-sulfamethoxazole (TMP-SMX) and nitrofurantoin (NF). Our data show that although the general pediatric population has lower resistance to ciprofloxacin, resistance levels are rising with increased usage. While NF susceptibility is historically stable, TMP-SMX resistance is slightly higher in children compared to adults. In both adults and children, antimicrobial resistance patterns vary according to clinical practice site, with ambulatory urology patients showing the highest resistance. This suggests that physician’s prescribing patterns contribute to antimicrobial resistance.

Antibiotic activity assessment of bacterial strains isolated from urine samples at Butare University Teaching Hospital (Buth) Laboratory

Background: Urinary tract infections (UTI) are common worldwide and affect all sexes and age groups. An estimated 20% or more of the female population suffers from some form of UTIs in their lifetime. Although antibiotics are the first choice of treatment for many urinary tract infections, antibiotic-resistant strains of bacterial species commonly associated with UTIs, are increasing worldwide. The purpose of this study was to determine the pathogen antimicrobial sensitivity trends of bacterial pathogens associated with UTIs. Methods & Materials: A retrospective study was carried out on bacteria isolated from the urine of patients at the BUTH laboratory between January 2006 and December 2010. Results: A total of 1611 pathogens have been found.The most commonly isolated bacteria were Escherichia coli (876 strains), Klebsiella Species (190 strains), Coagulase negative Staphylococcus (114 strains), Streptococcus species (97 strains), Proteus species (90 strains) and staphylococcus aureus (86 strains). Most of isolates were resistant to aminopenicillins (ampicillin and amoxicillin) and to trimethoprim- sulfamethoxazole (TMP-SMZ). Strains were rarely resistant to more expensive antibiotics (imipenem and cefotaxime). The most effective antibiotic to almost all isolates was imipenem, which is not commonly used in treatment of UTIs in Rwanda. Conclusion: The rate of amoxicillin and trimethoprim-sulfamethoxazole resistance to Enterobacteriaceae implies that another antibiotic should be used for empirical treatment and that there is a need for new generic drugs in Rwanda. Imipenem could be included as a reasonable alternative for the therapy of UTIs in Rwanda.

Antimicrobial resistence of H. pylori strains isolated in University Clinic of Infectious Diseases, Zagreb in 2008-2012 period

Background: Urinary tract infections (UTI) are commonworldwide and affect all sexes and age groups. An estimated 20% or more of the female population suffers from some form of UTIs in their lifetime. Although antibiotics are the first choice of treatment for many urinary tract infections, antibiotic-resistant strains of bacterial species commonly associated with UTIs, are increasing worldwide. The purpose of this study was to determine the pathogen antimicrobial sensitivity trends of bacterial pathogens associated with UTIs. Methods &Materials: A retrospective study was carried out on bacteria isolated from the urine of patients at the BUTH laboratory between January 2006 and December 2010. Results: A total of 1611 pathogens have been found.The most commonly isolated bacteria were Escherichia coli (876 strains), Klebsiella Species (190 strains), Coagulase negative Staphylococcus (114 strains), Streptococcus species (97 strains), Proteus species (90 strains) and staphylococcus aureus (86 strains). Most of isolateswere resistant toaminopenicillins (ampicillinandamoxicillin) and to trimethoprimsulfamethoxazole (TMP-SMZ). Strains were rarely resistant tomore expensive antibiotics (imipenem and cefotaxime). The most effective antibiotic to almost all isolates was imipenem, which is not commonly used in treatment of UTIs in Rwanda. Conclusion: The rate of amoxicillin and trimethoprimsulfamethoxazole resistance to Enterobacteriaceae implies that another antibiotic should be used for empirical treatment and that there is a need for new generic drugs in Rwanda. Imipenem could be included as a reasonable alternative for the therapy of UTIs in Rwanda.