Resistance Patterns Of Isolates Research Articles

Drug Resistance Pattern of Blood Culture Isolates in a Tertiary Care Hospital

Aim of the study: This study was carried out to find out In vitro susceptibility & resistance pattern of isolates were carried out by Kirby-Bauer disc diffusion method. Material and Methods: - The present study was conducted in Department of Microbiology in Era’s Lucknow Medical College and hospital. During the period of six months, 638 blood samples from septicemia suspected patients were received and processed routinely. Out of 638 blood culture, 90 (14.10%) were found positive for culture growth in which 38% were Gram’s positive and 62% were Gram’s negative. Out of 90 positive culture overall proportion of female (47) were found to be significantly higher them male (43). Results: Among 90 total pathogenic cases, 47(52.22%) were females and 43 (47.78%) were males. Oyekale T Oluwalana et al, (2022) [26] also showed similar data i.e, 57% of males and 42.4% female. In our study, 37 samples belong to age group from newborn to 25 years age (41.11%), 24 belongs to group 26 to 50 years age (26.67%), while 29 from age group 51 to 90 years (32.22%) were suspected of septicaemia. Staphylococcus aureus, coagulasenegative staphylococcus (CoNS) and Enterococcus species showed 100 % sensitivity to Vancomycin, Teicoplanin & Linezolid and Enterococcus species showed 90% sensitivity to Gentamicin, 87% sensitivity to Linezolid, moderately sensitivity 67% to Gentamycin and 80% to Teicoplanin and low sensitivity showed by Ciprofloxacin, Amoxiclav, 100% Resistance showed to Cefoxitin in staphylococcus aureus and coagulase-negative staphylococcus, enterococcus species. showed high sensitivity to Vancomycin (98%), Teicoplanin (98%), Chloramphenicol (89%) and (100%) sensitivity to linezolid. High level gentamycin resistance was 44%. Conclusion: Our study observed 100 % sensitivity to Tigecycline, Colistin and Piperacillin-Tazobactam in Escherichia coli, netilmicin was moderately sensitive to klebsiella and Escherichia coli. Higher resistance observed by Cefepime, Cefoperazone, Imipenem, Ceftriaxone.

Bacteriological Profile and Drug Resistance Pattern of Isolates of ICU Patients In Hospital Of Peshawar

Multidrug-resistant infectious diseases are one of the top causes of death and morbidity among hospitalized patients worldwide. Objective: This study’s aim was to assess the frequency of common bacterial pathogens, as well as their antibiotic sensitivity & resistance, in various Intensive care unit tertiary care hospitals. Methods: The current investigation was conducted from February to May 2021 in multiple ICU at a primary care hospital in Peshawar. Patients who were admitted to any of the hospital's four intensive care units (ICUs) and patients medically speculated of having an infection within 48 hours of arrival were included. Patients' laboratory samples were selected based on clinical suspicion. Antibiotic sensitivity testing was performed on the samples. Result: E. coli 33(26) was the most commonly isolated bacteria across all samples. “In NICU, CONS 17(67.78), in 7(28.28), in MICU, PICU E. coli, E. coli, Pseudomonas spp and Acinetobacter spp.11(22.39), and in E. coli, SICU 17(46.82) were predominantly isolated” “Amikacin 29(88.6), Cefuroxime 21(65), Klebsiella sp. to Cefoperazone+Salbactum 15(79), Pseudomonas to Tazobactum+Piperacillin 12(66), and Acinetobacter sp. to Sulbactum+Cefoperazone 12(66) are commonly used antibiotics against E. coli 12(56)”. Citrobacter spp. (67.8) was observed more followed by Proteus spp. (34.4) and Enterococcus (34.4). Conclusion: In the ICUs, infectious diseases and antimicrobial resistance are key barriers to patient outcome multidrug-resistant as well as expenditure. All intensive care units throughout the world face the issue of lowering the same.

Antimicrobial Susceptibility Pattern of Pseudomonas aeruginosa isolated from Clinical and Environmental Sources in Punjab, Pakistan

The increasing incidence of antimicrobial resistance is a public health concern, and Pseudomonas aeruginosa is known to be resistant to a variety of antibiotics. Antimicrobial resistance and the multiple antibiotic resistance (MAR) index of P. aeruginosa from environmental and clinical sources were studied in the current study. A total of 170 samples were evaluated, with 85 samples each from environmental sources and clinical settings. The isolates were subjected to microbial analysis and antimicrobial sensitivity testing. The findings revealed that 45.88 % (39) of the 85 clinical isolates tested for the presence of P. aeruginosa were positive. In terms of prevalence, there were significant variations (p 0.05) between the clinical samples. Wound samples had the highest isolation rate of 28.2%, while urine samples had the lowest (12.8%). P. aeruginosa was found in 38.8 % (33/85) of the samples isolated from environmental sources. In terms of prevalence, there was a highly significant difference (p 0.01) between the isolates. All of the positive isolates were completely resistant to cefuroxime and amoxicillin (100 %). The majority were also resistant to, cotrimoxazole (82%), nalidixic acid (82%), ciprofloxacin (86%), and tobramycin (69%). There was a substantial variation in the resistance patterns of isolates. The current study demand comprehensive measure to combat antimicrobial resistance in P. aeruginosa.

Neonatal sepsis and resistance pattern of isolates in Tertiary level neonatal unit: Time to evaluate the empirical antibiotics selection

Objective: To find out the most common organisms involved in neonatal sepsis origination and observe the pattern of antibiotic sensitivity and resistance of bacterial isolates. Materials and Methods: This descriptive cross-sectional study was conducted at the Department of Paediatrics Izzat Ali Shah Hospital, Wah Cantt. Out of 420 patients admitted with sepsis in NICU, 19.5% of patients with positive blood cultures were included in the study. A consecutive, non-probability sampling technique was used. Results: Out of 82 positive blood cultures gram-positive bacteria were observed in 19 patients (23.2%) and gram-negative bacteria were seen in 63 patients (76.8%). The most common gram-negative pathogens isolated were Acinetobacter (29.3%) and Klebsiella (24.4%). Staphylococcus aureus (12.2%) was the commonest gram-positive organism isolated. Gram-negative organisms showed maximum sensitivity to Tigecycline and Colistin and were resistant to Cefixime, Aztreonam, Amoxicillin, and Ceftriaxone. Gram-positive bacteria were sensitive to Teicoplanin, Linezolid, and Vancomycin while resistance was shown to penicillin and amoxicillin.Conclusion: The current study showed that gram-negative bacteria were the major contributors to sepsis in the respective setup and showed resistance to first-line antibiotics such as Penicillins and Cephalosporins. Strict infection control measures need to be implemented to avoid the emergence of resistant strains of pathogens in NICUs. This will help to reduce the incidence of neonatal sepsis leading to mortality.

Incidence and variation of microbiological profile of catheter-associated urinary tract infection in precise comorbidities associated with tribal sickle cell anemic patients of medical intensive care unit in a tribal tertiary care center

INTRODUCTION: Sickle cell anemia is a genetic hereditary disorder, with multifactorial cause for increase susceptibility, to bacterial infection leading to more intensive care unit (ICU) admission, morbidity, and mortality. When it is superadded by morbidities such as Type 2 diabetes mellitus (DM), chronic kidney disease (CKD), and chronic heart disease (CHD), chances of morbidity and mortality will increase multiple times in the ICU. AIM: The aim of this study was to find out the incidence, variation, and load in the microbiological profile of catheter-associated urinary tract infection (CAUTI), depending on the comorbidities associated with these sickle cell anemic tribal patients in the medical ICU (MICU) of a tribal tertiary care center. MATERIALS AND METHODS: This prospective study was conducted in MICU of a tribal tertiary care center from March 2019 to February 2020. It included diagnosed sickle cell anemic tribal patients with microbiologically confirmed cases of CAUTI following urinary catheterization for more than 48 h in the MICU. Demographic and clinical data of these patients were collected. Detailed investigations of the patients with antimicrobial susceptibility and resistance pattern of isolates were collected. RESULTS: In our study, the DAI rate in tribal sickle cell anemic patients was 8.7 per 1000 device days with an incidence of 7.8%. CAUTI was more common in female sex (86.7%), low socioeconomic status (80%), duration of urinary catheter up to first 7 days (66.7%), and age group above 40–60 years (33.3%). The most commonly associated microorganism was Staphylococcus aureus (46.6%) followed by Escherichia coli (13.3%) and Pseudomonas aeruginosa (13.3%). Associated comorbidities were Type 2 DM (20%), cerebrovascular accident (CVA) (20%), ST-segment elevation myocardial infarction (STEMI) (13.3%), CKD (13.3%), and CHD (6.6%). S. aureus 7 (46.6%) and Klebsiella pneumoniae 1 (6.6%) were found in Type 2 DM, Streptococcus pneumoniae 1 (50%) in STEMI, E. coli 2 (13.3%) in CKD and CVA, P. aeruginosa in 1 (6.6%) case each with CVA and septic shock, and Acinetobacter baumannii in 1 (6.6%) case with epilepsy. Resistant antibiotic was ceftriaxone 28.4% to S. aureus and 100% to E. coli. CONCLUSION: Our analysis precisely of this tribal population brings several important and unique findings, which will aid in the development of some new or update guidelines for the prevention of CAUTI to reduce morbidity and mortality in the MICU of a tribal tertiary care center.

Surveillance Stool Culture and its Association with Microbiologically Documented Infection During Febrile Neutropenia in Patients with Acute Leukemia (AL) Undergoing Induction Chemotherapy.

The study aimed at identifying the profile of gut colonization of patients with acute leukemia who underwent induction chemotherapy and its association with induction events and outcome. Baseline bacterial stool culture with resistance pattern of isolates were recorded. Multi-drug resistance was defined as resistance to at least two antibiotic classes including beta lactam and fluoroquinolones. During induction chemotherapy, blood and clinically indicated cultures were taken during febrile neutropenic episodes. Association studies were done between gut colonization and induction events/outcome. Among 109 patients enrolled, 71 (65.13%) patients undergoing induction chemotherapy were colonized with bacteria, with nearly 50% of colonizers harboring multi-drug resistant bacteria. Organisms isolated from stool pre-induction were mostly gram negative (98%), with Escherichia coli and Klebsiella pneumoniae being the commonest. 65.13% patients developed febrile neutropenia. Overall multi-drug resistant positivity during febrile neutropenia was 70.14%. Concordance of 8.45% was observed between isolates from stool and organisms isolated from cultures during febrile neutropenia. There were significant proportion of gut colonized gram-negative multi-drug resistance bacteria among patients with acute leukemia. There was a low concordance rate between baseline stool isolates and subsequent cultures during the induction. There was no significant association between gut colonization and induction events/outcomes studied.

ANTIMICROBIAL SUSCEPTIBILITY OF S. PNEUMONIAE STRAINS ISOLATED FROM CHILDREN WITH NASOPHARYNGEAL CARRIAGE

Streptococcus pneumoniae colonises the nasopharynx of children and could cause life-threatening diseases. As a result of the implementation of conjugate vaccines worldwide the spread of vaccine serotypes has decreased. In Bulgaria PCV10 was introduced in 2010 followed by changes in the invasive clones carrying resistance genes. The aim of our study is to determine the serotype distribution and resistance patterns of isolates from children carriers after vaccination. A total of 834 children were tested for S. pneumoniae and 21% showed positive culture results. All isolates were genotyped with PCR. We found that 85% of the positive samples are from children attending kindergartens and schools. The most frequent serotypes/serogroups were 6C (20%) and 24B/F (11.5%), followed by 3 (8.6%), 11A/D (8%), 35F (6.9%), 19A (6.3%), 23A (6.3%) and 15A/F (6.3%). The susceptibility to β-lactams was high and there were strains showing intermediate susceptibility to benzylpenicillin. This study found 76 (44%) MDR strains non-susceptible to at least 3 antibiotic classes and the most common resistance pattern was erythromycin-clindamycin-tetracycline.

Characterization of Mechanisms Lowering Susceptibility to Flumequine among Bacteria Isolated from Chilean Salmonid Farms.

Despite their great importance for human therapy, quinolones are still used in Chilean salmon farming, with flumequine and oxolinic acid currently approved for use in this industry. The aim of this study was to improve our knowledge of the mechanisms conferring low susceptibility or resistance to quinolones among bacteria recovered from Chilean salmon farms. Sixty-five isolates exhibiting resistance, reduced susceptibility, or susceptibility to flumequine recovered from salmon farms were identified by their 16S rRNA genes, detecting a high predominance of species belonging to the Pseudomonas genus (52%). The minimum inhibitory concentrations (MIC) of flumequine in the absence and presence of the efflux pump inhibitor (EPI) Phe-Arg-β-naphthylamide and resistance patterns of isolates were determined by a microdilution broth and disk diffusion assays, respectively, observing MIC values ranging from 0.25 to >64 µg/mL and a high level of multi-resistance (96%), mostly showing resistance to florfenicol and oxytetracycline. Furthermore, mechanisms conferring low susceptibility to quinolones mediated by efflux pump activity, quinolone target mutations, or horizontally acquired resistance genes (qepA, oqxA, aac(6′)-lb-cr, qnr) were investigated. Among isolates exhibiting resistance to flumequine (≥16 µg/mL), the occurrence of chromosomal mutations in target protein GyrA appears to be unusual (three out of 15), contrasting with the high incidence of mutations in GyrB (14 out of 17). Bacterial isolates showing resistance or reduced susceptibility to quinolones mediated by efflux pumps appear to be highly prevalent (49 isolates, 75%), thus suggesting a major role of intrinsic resistance mediated by active efflux.

Profiling of the bacterial pathogens associated with hospital acquired infections in hospitals within makurdi metropolis, middle belt, nigeria.

Background: Nosocomial bacteria are bacteria that cause diseases acquired from the hospital environments. Aim: This study looked into profile of bacterial pathogens associated with nosocomial infections in hospitals within Makurdi metropolis. Result: A total of 71 bacterial pathogens were encountered from 240 samples analysed from three hospitals in Makurdi metropolis. Of the 71 isolates, 46(64.8%) were Gram positive and 25(35.2%) were Gram negative. The Gram positive constituting S. aureus (50.70%) and staphylococcus spp (14.08%) while the Gram negative constituting E. coli (15.50%), klebsiella spp (7.04%) and P. aeruginosa (12.68%). Out of 21(29.58%) isolates cultured from hand swabs, the bacterial pathogens from hand swab at F M C was the highest 12(57.14%) followed by C H M 5(23.81%) while B M M C has the least profile of 4(19.05%). With regards to hospital air, the highest profile of nosocomial bacteria was also from F M C 8(61.54%), followed by B M M C 4(30.77%) while C H M had just only one isolate 1(7.69%). Of 21(29.58%) isolates from B M M C; 10(47.62%) S. aureus, 4(19.05%) Staphylococcus spp, 2(9.52%) P. aeruginosa and 5(23.81%) Escherichia coli were obtained. In C H M, out of 18(25.35%) bacterial pathogens evolved constituting 12(66.67%) S. aureus, 2(11.11%) Staphylococcus spp, 1(5.56%) P. aeruginosa and 3(16.67%) E. coli. Whereas, the profile of 32(45.07) isolates in Federal Medical Centre Makurdi constituting 14(43.75%) S. aureus, 4(12.50%) Staphylococcus spp, 6(18.75%) P. aeruginosa, 3(9.38%) E. coli and 5(15.63%) Klebsiella spp were obtained. The antibiotic susceptibility pattern to Staphylococcus spp reveals that the highest level of sensitivity were demonstrated by Cloxacillin and Ofloxacin with 50%, followed by Augumentin and Cefuroxime with 40%, Gentamicin (30%), Erythromycin (20%) and least sensitivity with Ceftriazone (10%) while Ceftazidime has the highest resistance recorded 0% sensitivity. E. coli has the highest sensitivity on Ceftazidime having 81.8% and Gentamicin 63.6%, Ofloxacin also displayed a high level of sensitivity to isolates tested with 63.6% sensitive, follow by Cefuroxime (45.5%).
 Conclusion: This study showed that nosocomial bacterial pathogens particularly, S. aureus, P. aeruginosa, Staphylococcus spp and enteric bacteria, E. coli and Klebsiella spp are the predominant pathogens associated with infections acquired in hospital environment.So, information on resistance patterns of isolates encountered in this study will assist the clinicians in making improvement in management of nosocomial infections.
 Bangladesh Journal of Medical Science Vol.18(2) 2019 p.368-378

Antibacterial properties of Carum copticum essential oil against Streptococcus mutans and Streptococcus sobrinus isolated from canine dental plaque

Dental caries is amongst the most prevalent oral diseases in both humans and dogs. Streptococcus mutans and Streptococcus sobrinus (mutans streptococci) are the major cariogenic bacteria isolated from dental caries. Since these bacteria generally show resistance to common antibiotics, natural products such as plant essential oils could be a good substitute. For this study, we aimed to evaluate the antibacterial activity of Carum copticum essential oil against Streptococcus mutans and Streptococcus sobrinus. Twenty canine dental plaque samples were collected and the presence of S. mutans and S. sobrinus in the samples was confirmed using biochemical, culture and polymerase chain reaction (PCR) assays. The resistance patterns of isolates were determined using a disc diffusion method according to the Clinical Laboratory Standards Institute protocol against the following antimicrobials: chloramphenicol, tetracycline, penicillin, erythromycin, ceftriaxone, cefotaxime, vancomycin and azithromycin. The antibacterial activities of Carum copticum essential oil were based on the disc diffusion method as well on a determination of the minimum inhibitory (MIC<sub>50</sub>) and minimum bactericidal concentration values. S. mutans and S. sobrinus were isolated in 8 (40%) and 2 (10%), respectively, of plaque samples. Most of these isolates were determined to display multidrug resistance patterns to the eight antibiotics evaluated. Screening of the antibacterial activity of the essential oil indicated that MIC<sub>50</sub> and minimum bactericidal concentration values were 20 µg/ml and 80 µg/ml, respectively, and that the zone of inhibition in the disc diffusion method ranged from 2 to 5 mm for serial concentrations of the essential oil. Based on our results, we suggest that Carum copticum essential oil exerts antibacterial effects against Streptococcus mutans and Streptococcus sobrinus and may be a useful treatment for carious lesions with bacterial aetiologies.

Determinants of Virulence and Antimicrobial Susceptibility in Non-O1, Non-O139 Vibrio cholerae Isolates.

ABSTRACT INTRODUCTION In the Caribbean region, acute diarrheal diseases caused by the Vibrio genus have increased in recent years, following the 2010 earthquake in Haiti. Based on its capsular lipopolysaccharide, Vibrio cholerae is classified into more than 200 serogroups, divided into O1, O139 and non-O1, non-O139. Non-O1 serogroups produce clinical features ranging from mild diarrhea to severe dehydration. In Cuba, circulation of non-O1, non-O139 V. cholerae has been reported both in outbreaks and sporadic cases. OBJECTIVE Describe the antimicrobial susceptibility of V. cholerae to the drugs of interest used in its treatment and verify the presence of enzymatic virulence factors. METHODS A descriptive, cross-sectional study was conducted in January through November 2014, based on 125 non-O1, non-O139 V. cholerae isolates obtained during 2013 and 2014 from patients with acute diarrheal disease (isolates from the National Reference Laboratory for Acute Diarrheal Diseases of the Pedro Kouri Tropical Medicine Institute, Havana). Bacteriological identification was performed according to conventional methods. Antimicrobial susceptibility was determined by the Bauer-Kirby agar diffusion method. The technique described by Robinson in 1986 was used to determine virulence factors, hemolytic activity and enzyme factors (DNase, elastase, gelatinase), and Karagozova’s method for the enzyme lecithinase. RESULTS Highest percentages of sensitivity were obtained for azithromycin (98.4%), doxycycline (97.6%) and ciprofloxacin (96.8%), and highest resistance values for ampicillin (60%), sulfonamide (46.4%) and trimethoprim–sulfamethoxazole (32%). Six resistance patterns were detected, four found in Cuba for the first time, as well as six patterns of multidrug resistance (4.8%). All isolates had at least two extracellular enzymes as virulence factors. The most frequent were gelatinase (90.4%) and lecithinase (77.6%). The percentage of virulence factors was lower in the group of isolates resistant to ≥2 antimicrobials. An inverse relationship was found between presence of enzymatic virulence factors and resistance in the isolates studied. CONCLUSIONS The results suggest that azithromycin, doxycycline and ciprofloxacin should continue to be used for treatment of V. cholerae-caused infections, and confirmed the presence of four new resistance patterns in isolates circulating in Cuba.

Determination of antibiotics sensitivity profiles of bacteria isolated from raw milk

The extensive progress of dairy sectors in a developing country like Bangladesh, led to widespread use of antibiotics to improve the health and productivity of animals. Prolonged usage may lead to antibiotic residues in foods of animal origin; hence, the emergence of antimicrobial resistant microorganisms. Accurate data on the antibiotic usage in livestock treatment, antibiotic residues and antimicrobial resistances in raw milk in Bangladesh are lacking. This study aimed to investigate the types and usages of antibiotics in cattle, their potential microbial resistances in raw milk samples. To do so, a total of 54 raw milk samples were evaluated and the bacterial isolates were identified and measured for resistance to 4 antibiotics most commonly used during bacterial infection Bangladesh. Amongst all 54 (100%) isolates were positive to S. aureus and 36 (66.67%) isolates were positive to E coli. Determination of the antibiotic resistance pattern of isolates showed that all isolates of S. aureus were resistant to cefoxitin (81.48%), ampicillin (64.81%), ciprofloxacin (51.85%), and gentamycin (70.37%). E. coli showed resistance to cefoxitin (69.44%), ampicillin (83.33%), ciprofloxacin (77.78%), and gentamycin (86.11%). However multidrug resistance pattern was also found. The obtained results provide evidence that antimicrobial resistant strains of the above pathogens have become remarkably widespread in raw milk. This requires better management for antibiotic usages among livestock farmers to control sources of food contamination and reduce the health risks associated with the development of resistant microbial strainsAsian J. Med. Biol. Res. September 2016, 2(3): 396-401

Trends in antimicrobial resistance in equine bacterial isolates: 1999–2012

This study aimed to identify changing antimicrobial resistance patterns in isolates commonly obtained from equine clinical submissions. Laboratory records from 1999 to 2012 were searched for equine samples from which...

Emergence of KPC-producing Klebsiella pneumoniae in Uruguay: infection control and molecular characterization.

We describe the first outbreak of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP), the infection control measures adopted and the shift in resistance patterns of isolates during antibiotic treatment. The ST258 KPC-KP strain exhibited a multiresistant antibiotic phenotype including co-resistance to gentamycin, colistin and tigecycline intermediate susceptibility. Isolates before and after treatment had different behaviour concerning their antibiotic susceptibility and the population analysis profile study. A progressive increase in the aminoglycosides (acquiring amicacin resistance) and β-lactam MICs, and a decreased susceptibility to fosfomycin was observed throughout the administration of combined antimicrobial regimens including meropenem. A high meropenem resistance KPC-KP homogeneous population (MIC 256 Jg/mL), could arise from the meropenem heterogeneous low-level resistance KPC-KP population (MIC 8 Jg/mL), by the selective pressure of the prolonged meropenem therapy. The kpc gene was inserted in a Tn4401 isoform a, and no transconjugants were detected. The core measures adopted were successful to prevent evolution towards resistance dissemination.

English

The aim of this study was to determine the prevalence of nasal carriage of Staphylococcus aureus among patients and personnel of private centers at Casablanca, and to determine the resistance pattern of isolates. The carriage of virulence toxin genes by the methicillin resistant strains was also investigated. This study was conducted from November 2008 to February 2009. Nasal swabs were taken from 145 and 42 patients and personnel respectively. The susceptibility testing to 16 antibiotics was performed using the agar disc diffusion method. Minimum inhibitory concentrations (MICs) of oxacillin were determined by the agar dilution method for all strains demonstrating resistance to cefoxitin. In addition, resistant isolates were examined for the existence of the mecA gene by polymerase chain reaction (PCR). Furthermore, the carriage of 22 virulence toxin genes among strains showing resistance to cefoxitin was investigated by PCR Multiplex. The prevalence of nasal carriage of S. aureus was 32.4% (n=47) and 38.1% (n=16) in patients and personnel, respectively. Patients’ strains showed 16 resistance patterns against only 4 in personnel strains. No S. aureus isolates were found to be resistant to lincomycin, pristinamycin, gentamicin, chloramphenicol, trimethoprim-sulfamethoxazole, rifampicin and vancomycin, while over 90% (n = 59) were resistant to penicillin G. For the other antibiotics, the percentage of resistance varied between 2.63 and 18.75%. One S. aureus (1.6%) was methicillin resistant by possession of mecA gene. This isolate harboured the staphylococcal enterotoxin genes sec, sed, sell, selm, selo, ser and toxic shock syndrome toxin gene (tst). Investigation of S. aureus nasal carriage and characterization of isolates among patients undergoing hemodialysis is important to develop infection prevention and to limit the spread of methicillin resistant S. aureus (MRSA) strains. Key words: Hemodialysis centers, patients, personnel, Staphylococcus aureus, nasal carriage, antibiotic susceptibility, methicillin resistance, toxin genes.

Characterization of <i>Staphylococcus aureus</i> infections among children in an outpatient clinic, China

Objective: We aimed to investigate the epidemiology and identify antibiotic resistance patterns of isolates from children with skin and soft tissue infections attending an outpatient clinic in Southern China. Method: An observational study of outpatient pediatric patients was conducted in a rural area of Guangxi. Infections were characterized in 230 patients and staphylococcal isolates tested for susceptibility to a range of antibiotics. Results: Among the 307 patients, 38.5% were infants. Culture yielded Staphylococcus aureus (S. aureus) in 230 patients, of which 24 (10.4%) were methicillin-resistant S. aureus (MRSA). Staphylococcal strains were most isolated from hand, foot and umbilicus. The 1-12 mon group had the highest staphylococcal infection rate (86%), followed by the 6-12 year group, but MRSA was more common in the older children (19.5% of S. aureus). MRSA had significantly more resistance than MSSA to chloromycin (46% vs 11%), clindamycin (67% vs 19%), gentamicin (33% vs 2%), rifampicin (25% vs 2.9%), and sulphamthoxazole-trimethoprim (17% vs 3%). Conclusion: S. aureus remains a leading cause of pediatric skin and soft tissue infections. Over 10% of isolates were methicillin-resistant with high rates of resistance to non-beta lactam antibiotics, reducing options for therapy and limiting choices for empirical treatment.

Epidemiological, clinical features and susceptibility pattern of shigellosis in the buea health district, Cameroon

BackgroundShigellosis is an acute invasive enteric infection caused by bacteria belonging to the genus Shigella; it is clinically manifested by bloody diarrhoea. Shigellosis is endemic in many developing countries including Cameroon and also occurs in epidemics causing considerable morbidity and mortality. This study evaluated the epidemiological and clinical features of Shigella and the resistance pattern of isolates to commonly used antibiotics in the Buea Health District in Cameroon, from April to August, 2010.ResultsOf the 223 stool samples cultured, 10 (4.5%) yielded Shigella species. Isolation rate was observed to be more in children below 15 years (7.89%), and also higher in rural areas (6.35%). All 10 isolates showed resistance to at least two antibiotics and 9 (90%) were multi-drug resistant. The highest resistance rates were encountered with cotrimoxazole (90%) and amoxicillin (80%). Least resistance was observed with azithromycin (10%).ConclusionShigellosis is more prevalent in children below 15 years in the Buea District. There is a high level of resistance to most of the antibiotics used for the treatment of shigellosis including extended-spectrum beta-lactamases (ESBLs) as well as evidence of resistance to quinolones. Azithromycin was found to be the drug of choice for shigellosis in this setting.

1373 Bacterial Contamination of Intensive Care Units (NICU) and Determination of Antibiotics Resistance Patterns in Isolates in Hamadan, West of Iran

1373 Bacterial Contamination of Intensive Care Units (NICU) and Determination of Antibiotics Resistance Patterns in Isolates in Hamadan, West of Iran

Highly Variable Patterns of Antimicrobial Resistance in CommensalEscherichia coliIsolates from Pigs, Sympatric Rodents, and Flies

Antimicrobial-resistant Escherichia coli strains from pigs, sympatric rodents, and flies from two large farms in the Czech Republic with different antibiotic exposure histories were characterized based on antimicrobial resistance genes, integrons, and macrorestriction DNA profiles. Isolates of E. coli were tested for susceptibility to 12 antimicrobial agents according to the standard disk diffusion method. In resistant isolates, polymerase chain reaction was used to detect antibiotic resistance genes, integrase genes, and gene cassettes. Pulsed-field gel electrophoresis (PFGE) was used for molecular subtyping of E. coli. In farm A (long-term use of amoxicillin only), 75% (n = 198), 65% (n = 49), 11% (n = 139), and 82% (n = 177) of E. coli isolates from piglets, sows, sympatric rodents, and flies, respectively, were antibiotic resistant. In farm B (various antibiotics commonly used), 53% (n = 154), 69% (n = 98), and 54% (n = 74) of E. coli isolates from piglets, sows, and sympatric rodents, respectively, were antibiotic resistant. In both farms, the highest resistance prevalence was to tetracycline, and resistance patterns of isolates were greatly variable. Isolates with the same resistance phenotype, genes, and PFGE profile were found in pigs and flies. Isolates from rodents showed unique PFGE profiles. Close contact of sympatric rodents and flies with pigs or their products was associated with colonization of rodents and flies with resistant bacteria or transfer of resistance genes found in pig intestinal flora.

Antimicrobial Susceptibility of Shiga Toxin-ProducingEscherichia coliIsolated from Organic Dairy Farms, Conventional Dairy Farms, and County Fairs in Minnesota

This study compared the antimicrobial susceptibility of Shiga toxin-producing Escherichia coli (STEC) isolates from organic dairy farms, conventional dairy farms, and Minnesota county fairs. A total of 83 STEC isolates (43 O157 and 40 non-O157 STEC) were tested for antimicrobial susceptibility as determined by the automated broth microdilution method. Resistance to tetracycline was identified in 19 (23%) isolates and to sulphadimethoxine in 40 (48%) isolates. Half of the STEC isolates were resistant to at least one antimicrobial agent. Resistance to at least one antimicrobial agent was observed in 18 (62%) isolates from conventional farms and in 11 (48%) isolates from organic farms. Resistance to at least one antimicrobial agent was more frequent in isolates from calves (77%) than from cows (39%). Multidrug resistant patterns were more common in non-O157 STEC than O157 STEC. This study provides data to document the degree of STEC antimicrobial resistance from dairy cattle sources in Minnesota. The use of antimicrobial agents on farms, and other environmental influences, may affect resistance patterns in isolates from cattle sources. Systematic surveillance of STEC from cattle could potentially detect emergence of antimicrobial resistance that may be spread to humans through the food chain.