Clinical Laboratory Standards Institute Guidelines Research Articles

Molecular diagnosis and anti-microbial resistance patterns among Shigella spp. isolated from patients with diarrhea.

This study aims to determine the serogroup distribution and molecular diagnosis, as well as antimicrobial resistance profiles among Shigella spp. isolated from patients with diarrhea in Kerman, southeast of Iran. Shigella species are frequent cause of bacterial dysentery worldwide. Previous studies have been reported that S. sonnei and S. flexneri are the most prevalent serogroups in various parts of Iran. A total of 624 stool samples were randomly collected from patients with diarrhea from June 2013 to August 2014. Biochemical and serological characterizations were performed for identifying Shigella spp. In addition, the multiplex PCR assay was carried out for the detection and differentiation of three pathogenic Shigella spp. Antibiotic susceptibility testing was performed according to the Clinical Laboratory Standards Institute (CLSI) guidelines. Fifty six (9%) Shigella strains were isolated from stool samples. The most common species were S. flexneri 31(55.4%), followed by S . sonnei 18(32.1%) and S. boydii 7(12.5%). S. dysentery was not detected in the present study. All the isolates that identified by serological test as Shigella spp. were confirmed by the multiplex PCR method. The highest rate of resistance was observed for ampicillin and trimethoprim-sulphamethoxazole antibiotics with 52(92.9%) resistant, followed by tetracycline 44(78.6%) and cefotaxime 33(58.9%). All Shigella isolates were susceptible to ciprofloxacin. A significant relationship was found between the Shigella species and cefotaxime resistance (p<0.05). S. flexneri was found as the most prevalent serogroup causing shigellosis. The high rate of resistance to third-generation cephalosporins limits the treatment options available for the management of shigellosis in Kerman, Iran.

Biological activity of Cymbopogon schoenanthus essential oil.

IntroductionA number of plant species, including Cymbopogon schoenanthus, are traditionally used for the treatment of various diseases. C. schoenanthus is currently, traded in the Saudi markets, and thought to have medicinal value. This study aimed at investigating the biological activities of C. schoenanthus against both Gram-positive and Gram-negative bacteria and to identify its chemical ingredients.Materials and methodsThe inhibitory effects of water extracts of C. schoenanthus essential oils were evaluated against ten isolates of both Gram-positive and Gram-negative bacteria using the agar well diffusion and dilution methods. The minimum inhibitory concentration (MIC) was assayed using the Broth microdilution test on five of the ten isolates. The death rates were determined by the time kill assay, done according to the Clinical Laboratory Standards Institute (CLSI) guidelines. The chemical composition of the essential oils of the plant was performed using GC/MS.ResultsThe C. schoenanthus essential oil was effective against Escherichia coli, Staphylococcus aureus, methicillin-sensitive (MSSA) S. aureus (MRSA) and Klebsiella pneumoniae. The essential oil was not effective against Staphylococcus saprophyticus at the highest concentration applied of >150 μg/ml. The MIC values were as follows: 9.37 μg/ml for E. coli 4.69 μg/ml for S. aureus (MRSA), 2.34 mg/ml for MSSA and 2.34 μg/ml for K. pneumoniae. The time-kill assay indicated that there was a sharp time dependent decline in K. pneumoniae counts in the presence of the oil. This is in contrast to a gradual decline in the case of S. aureus under the same conditions. The eight major components of the essential oil were: piperitone (14.6%), cyclohexanemethanol (11.6%), β-elemene (11.6%), α-eudesmol (11.5%), elemol (10.8%), β-eudesmol (8.5%), 2-naphthalenemethanol (7.1%) and γ-eudesmol (4.2%).ConclusionThe results of the present study provide a scientific validation for the traditional use of C. schoenanthus as an antibacterial agent. Future work is needed to investigate and explore its application in the environmental and medical fields. In addition, to evaluating the efficacy of the individual ingredients separately to better understand the underlying mechanism.

High prevalence of plasmid-mediated quinolone resistance determinants in Enterobacter cloacae isolated from hospitals of the Qazvin, Alborz, and Tehran provinces, Iran.

Plasmid-mediated quinolone resistance (PMQR) is a growing clinical concern worldwide. The main aims of this study were to detect qnr-encoding genes and to evaluate the clonal relatedness of qnr-positive Enterobacter cloacae isolates. A total of 116 E. cloacae isolates that were not susceptible to quinolone were obtained from seven hospitals in Tehran, five hospitals in Qazvin, and two hospitals in Karaj (Iran). Bacterial identification was performed using standard laboratory methods and API 20E strips. Quinolone resistance was determined using the Kirby-Bauer disk diffusion method according to the Clinical Laboratory Standards Institute (CLSI) guidelines. PCR and sequencing were employed to detect qnrA, qnrB, and qnrS genes, and clonal relatedness was assessed using the enterobacterial repetitive intergenic consensus (ERIC)-PCR method. In total, 45 (38.8%) and 71 (61.2%) of isolates showed high- and low-level quinolone resistance, respectively, and qnr-encoding genes were detected in 70 (60.3%) of them. qnrB1 [45 (38.8%) isolates] was the most commonly detected gene, followed by qnrS1 [28 (24.1%) isolates] and qnrB4 [18 (15.5%) isolates] either alone or in combination with other genes. The results of the ERIC-PCR revealed that 53 (75.7%) qnr-positive isolates were genetically unrelated. This study describes, for the first time, the high prevalence of the qnrB1, qnrS1, and qnrB4 genes among E. cloacae isolates in Iran. The detection of qnr genes emphasizes the need for establishing tactful policies associated with infection control measures in hospital settings in Iran.

Comparative In Vitro Efficacy of Doripenem and Imipenem Against Multi-Drug Resistant Pseudomonas aeruginosa.

To compare the in vitro efficacy of doripenem and imipenem against multi-drug resistant (MDR) Pseudomonas aeruginosa from various clinical specimens. Descriptive cross-sectional study. Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from November 2012 to November 2013. MDR Pseudomonas aeruginosa isolates from various clinical samples were included in the study. Susceptibility of Pseudomonas aeruginosa against doripenem and imipenem was performed by E-test strip and agar dilution methods. The results were interpreted as recommended by Clinical Laboratory Standard Institute (CLSI) guidelines. The maximum number of Pseudomonas aeruginosa were isolated from pure pus and pus swabs. In vitro efficacy of doripenem was found to be more effective as compared to imipenem against MDR Pseudomonas aeruginosa with both E-test strip and agar dilution methods. Overall, p-values of 0.014 and 0.037 were observed when susceptibility patterns of doripenem and imipenem were evaluated with E-test strip and agar dilution methods. In vitro efficacy of doripenem was found to be better against MDR Pseudomonas aeruginosaas compared to imipenem when tested by both E-test and agar dilution methods.

An outbreak of Pantoea agglomerans infection in the neonatal intensive care unit at Teaching Hospital, Kandy, Sri Lanka

Introduction: Pantoea agglomerans is an opportunistic pathogen which causes blood stream infection (BSI) due to contaminated intravenous fluids. Objective: To investigate an outbreak of BSI in a neonatal intensive care unit (NICU) at Teaching Hospital Kandy (THK). Method: Blood culture samples were collected from the neonates on admission to the NICU and 2 to 3 days later on clinical suspicion of BSI. The blood culture samples were processed according to standard methods and antibiotic susceptibility tests were carried out as per Clinical Laboratory Standards Institute guidelines. The environmental screening samples were cultured and identified using standard microbiological methods. Results: Of the 55 blood cultures, 14 were positive for P. agglomerans . Nine of the 14 neonates responded to treatment with susceptible antibiotics. None of the environmental samples were positive for P. agglomerans species. Conclusion: P. agglomerans was responsible for the outbreak of BSI in the NICU at THK.

Molecular Identification and Echinocandin Susceptibility of Candida parapsilosis Complex Bloodstream Isolates in Italy, 2007–2014

The Candida parapsilosis group encompasses three species: C. parapsilosis, C. orthopsilosis, and C. metapsilosis. Here, we describe the incidence and echinocandin susceptibility profile of bloodstream isolates of these three species collected from patients admitted to an Italian university hospital from 2007 to 2014. Molecular identification of cryptic species of the C. parapsilosis complex was performed using polymerase chain reaction amplification of the gene encoding secondary alcohol dehydrogenase, followed by digestion with the restriction enzyme BanI. Minimum inhibitory concentrations were determined using the broth microdilution method according to European Committee for Antimicrobial Susceptibility Testing (EUCAST EDef 7.2) and Clinical Laboratory Standards Institute (CLSI M27-A3) guidelines, and the results were compared with those obtained using the E-test and Sensititre methods. Of the 163 C. parapsilosis complex isolates, 136 (83.4%) were identified as C. parapsilosis, and 27 (16.6%) as C. orthopsilosis. The species-specific incidences were 2.9/10,000 admissions for C. parapsilosis and 0.6/10,000 admissions for C. orthopsilosis. No resistance to echinocandins was detected with any of the methods. The percent essential agreement (EA) between the EUCAST and E-test/Sensititre methods for anidulafungin, caspofungin, and micafungin susceptibility was, respectively, as follows: C. parapsilosis, 95.6/97.8, 98.5/88.2, and 93.4/96.3; C. orthopsilosis, 92.6/92.6, 96.3/77.8, and 63.0/66.7. The EA between the CLSI and E-test/Sensititre methods was, respectively, as follows: C. parapsilosis, 99.3/100, 98.5/89.0, and 96.3/98.5; C. orthopsilosis, 96.3/92.6, 100/81.5, and 92.6/88.9. Only minor discrepancies, ranging from 16.9% (C. parapsilosis) to 11.1% (C. orthopsilosis), were observed between the CLSI and E-test/Sensititre methods. In conclusion, this epidemiologic study shows a typical C. parapsilosis complex species distribution, no echinocandin resistance, and it reinforces the relevance of using commercially available microbiological methods to assess antifungal susceptibility. These data improve our knowledge of the national distribution of species of the psilosis group, as there are very few studies of these species in Italy.

Bacteriology and antimicrobial susceptibility of ESBLs producers from pus in patients with abdominal trauma associated intra-abdominal infections.

Intra-abdominal infections (IAIs) caused by ESBLs producing bacteria have become a serious clinical concern worldwide as the prevalence of bacterial resistance to antibiotics continues to increase. The objective of this study was to analyze the bacteriology and antimicrobial susceptibility of ESBLs producers using pus samples from IAIs patients caused by abdominal trauma. A total of 113 pus samples aspirated from IAIs patients were collected. The BACTEC 9120 and Vitek 2 system were used for detecting positive pathogens and confirming ESBLs production. The results of susceptibility were determined following the Clinical Laboratory Standards Institute guidelines. Among the pathogens causing IAIs, Escherichia coli (E. coli) (29.1%) was the most commonly isolated, followed by Klebsiella pneumoniae (K. pneumoniae) (22.5%). The incidence rates of ESBLs production among E. coli, K. pneumoniae, and Klebsiella oxytoca were 69.6, 45.1, and 25.0%, respectively. All pathogens had high resistance rates against studied antibiotics, with imipenem (88.7%) and ertapenem (90.7%) remaining the only practical options. Trend analysis documented an increase in ESBLs producing E. coli and K. pneumoniae, and a decrease in susceptibility for carbapenems among ESBLs producing E. coli and K. pneumoniae. Escherichia coli and K. pneumoniae were the major pathogens causing abdominal trauma associated IAIs. The most active agents against ESBLs producing E. coli and K. pneumoniae were ertapenem and imipenem. However, the ESBLs rates were alarmingly high and increasing among IAIs associated gram-negative bacilli infections in China, and most agents exhibited decreased susceptibility against ESBLs producing pathogens.

Presence of New Delhi metallo-β-lactamase gene (NDM-1) in a clinical isolate of Acinetobacter junii in Argentina.

Fil: Montana, Sabrina Daiana. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Houssay. Instituto de Investigaciones en Microbiologia y Parasitologia Medica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiologia y Parasitologia Medica; Argentina

Lower Respiratory Tract Infections in Intensive Care Units. A Four Year Study from North India

Title: Lower respiratory tract infections in intensive care units. A four year study from North India. Study Design: Prospective study Place and Duration of Study: Sher-i-Kashmir Institute of Medical Sciences, Srinagar Kashmir. Four years (July 2010 and June 2014). Methodology: A prospective analysis of respiratory specimens from various intensive care units (ICUs) was done over a period of four years. Antimicrobial susceptibility of culture positive isolates to various antibiotics was performed as per Clinical Laboratory Standards Institute (CLSI) guidelines. Original Research Article Bali et al.; BJMMR, 11(7): 1-9, 2016; Article no.BJMMR.21636 2 Gram-negative bacteria (GNB) were screened for extended spectrum β-lactamase (ESBL) and metallo-β-lactamase (MBL) production; whereas methicillin and vancomycin resistance was searched in staphylococci and enterococci isolates respectively. Results: The frequencies of Gram-positive and Gram-negative bacteria were 26% and 68% respectively with yeast recovered in 8% of the specimens. K. pneumoniae and Acinetobacter spp were the most common Gram-negative bacteria and S. aureus the most common Gram-positive one. High level resistance to all the antimicrobials was seen; with K. pneumoniae being the most multidrug resistant GNB isolated in the ICU setting. ESBL production was also highest in K. pneumoniae isolates (67.1%). Also 59.6% of Acinetobacter isolates were found to be MBL producers. Methicillin resistance was seen in 48% of S. aureus and 85.5% of coagulase negative staphylococci (CoNS) isolates with vancomycin resistance seen in 6.7% of enterococcal isolates. Conclusion: An increasing trend over the years in the antibiotic resistance of respiratory pathogens in ICUs of this north Indian state was seen that calls for urgent measures to limit their continued rise.

Evaluation of antimicrobial effect of azadirachtin plant extract (Soluneem (™)) on commonly found root canal pathogenic microorganisms (viz. Enterococcus faecalis) in primary teeth: A microbiological study.

The aim of this study is to evaluate the antimicrobial activity of Soluneem ™ when used as an irrigating solution along with other commonly used irrigating solution sodium hypochlorite (NaOCl) against Enterococcus faecalis. Microorganism used in this study was E. faecalis (Microbial Type Culture Collection 439). Test substance used was Soluneem ™, which was obtained from Vittal Mallya Scientific Research Foundation (VMSRF), Bengaluru. This study was conducted in a microbiology laboratory (Biocare Research India Pvt., Ltd. Laboratory, Ahmedabad, Gujarat) to evaluate the antimicrobial effect of Soluneem ™ (Azadirachtin) on E. faecalis. Antimicrobial activity testing was performed using the macrobroth dilution method according to the Clinical Laboratory Standards Institute guidelines. All determinations were performed thrice. Minimum bactericidal concentration (MBC) was seen as 2.6% for Soluneem ™ while the same was seen at 0.1% for NaOCl. Independent sample t-test was carried out to compare the MBC of Soluneem ™ and NaOCl, which showed that there was no statistically significant difference between them, i.e., 2.6% Soluneem ™ was as effective as 0.1% NaOCl. Soluneem ™ showed antimicrobial activity against E. faecalis at various concentrations. It was also found that the efficacy of Soluneem ™ at 2.6% concentration and above was relatively similar to that of gold standard irrigating solution (NaOCl) on inhibition of E. faecalis.

Bacteriological profile and antibiogram of neonatal septicemia in a tertiary care hospital

Background: Neonatal sepsis is a clinical syndrome which is characterised by signs and symptoms of infection which may or may not be accompanied by bacteraemia within the first month of life. The bacteriological profile of neonatal sepsis is under constant change with the advances in the diagnosis and treatment. Blood culture is still the mainstay of investigation of potential sepsis in spite of the recent advances in molecular diagnosis of fungal and bacterial sepsis. Most common bacterial organisms responsible for neonatal septicaemia in developing countries like Bangladesh, India, Nigeria, Pakistan, are Klebsiella, Escherichia coli, Enterobacter etc. The present study was undertaken to describe the spectrum of the isolates in cases of neonatal septicaemia, and their antimicrobial susceptibility pattern. The study was carried out over a one year period. Method: A total of 357 suspected patients of neonatal septicaemia were included in the study. Blood samples were collected with aseptic precautions preferably prior to the initiation of empiric antibiotic therapy. The bottles were incubated aerobically at 370 C for 7 days and subcultured on blood agar and Mac Conkey agar. If growth appeared the isolates were processed as per standard microbiological techniques and the isolates were identified. Antibiotic sensitivity testing was performed on Mueller?Hinton agar plates by modified Kirby?Bauer disk diffusion method as per Clinical Laboratory Standard Institute guidelines. Results: Of the 357 samples studied, growth was observed in 154 samples. Gram positive organisms constituted 37.66% and gram negative bacilli constituted 62.34% of the isolates. The predominant pathogens isolated were Klebsiella species, Coagulase Negative Staphylococci, Staphylococcus aureus followed by Non fermenting gram negative bacilli. 71.43% of the Staphylococcus aureus isolates were found to be methicillin resistant.96.05% of the Enterobacteriaceae were found to be Extended Spectrum Beta Lact

Bacteriological profile and antimicrobial resistance patterns of bloodstream infections in a tertiary care hospital, Eastern India

Introduction: Bloodstream infections (BSIs) are associated with a high mortality rate of 20%-50%. Blood culture is paramount to identify causative agents of BSIs to choose an appropriate antimicrobial therapy. Objectives: The present study was undertaken to analyze the various microorganisms causing BSIs and study their antimicrobial resistance patterns in a tertiary care hospital, Eastern India. Materials and Methods: A total of 239 blood specimens from clinically suspected cases of BSIs were studied for 6 months from July 2015 to December 2015. Blood specimens were incubated in BacT/ALERT ® 3D system (bioMerieux, Durham, NC, USA) a fully automated blood culture system for detection of aerobic growth. Identification and antimicrobial susceptibility testing were conducted on VITEK ® 2 (bioMerieux, Durham, NC, USA) as per Clinical Laboratory Standards Institute guidelines. Results: Out of 239 specimens, 41 (17.2%) yielded growth of different microorganisms. From these isolates, 20 (48.8%) were Gram-negative bacilli, 18 (43.9%) were Gram-positive cocci and rest 3 (7.3%) were yeasts. Among Gram-negative bacilli, Klebsiella pneumoniae sub spp. pneumoniae (70%) was most commonly isolated. Coagulase-negative staphylococci (88.9%) were the most common isolate among Gram-positive cocci. All three Candida spp. isolated were nonalbicans Candida (two Candida tropicalis and one Candida krusei ). Gram-negative isolates were least resistant to tigecycline and colistin. All Gram-positive cocci were sensitive to linezolid. Conclusion: Monitoring of data regarding the prevalence of microorganisms and its resistance patterns would help in currently prescribing antimicrobial regimens and improving the infection control practices by formulating policies for empirical antimicrobial therapy.

Identification of the bacterial isolates in neonatal septicaemia and their antimicrobial susceptibility in a tertiary care hospital in Uttarakhand, India: a retrospective study

Background: Neonatal sepsis refers to systemic bacterial infection documented by positive blood culture in the first four weeks of life and is one of the four leading causes of neonatal mortality and morbidity in India. This study was a retrospective study to identify the bacterial isolates in neonatal septicaemia and their antimicrobial susceptibility in a tertiary care hospital in Uttarakhand, India from January 2013 to June 2015. Methods: Blood culture in newborns with clinical sign of septicaemia was retrospectively studied. Antimicrobial susceptibility testing was performed by Kirbuay -bauer disc diffusion susceptibility method in accordance to clinical laboratory standard institute guidelines (CLSI) . Results: 10.3% (124 /1200) cases of septicaemia could be confirmed by blood culture. Of these Gram negative could be isolated in (62%) of cases and (38%) were of gram positive isolates. Kliebsiella was the predominant pathogen (42.8%) among the gram negative pathogens followed by E coli (18.1%). CONS (57.4%) was the predominant gram positive pathogen. Of the Gram positives isolates 6% were methicillin resistant S.aureus (MRSA). Polymyxin (77.8%) and tigecycline (72%) were most effective drugs against gram negative isolates were as gram positive organisms showed maximum sensitivity to vancomycin (90%) and linezolid (87%). Conclusions: This study highlights the growing resistance to commonly used antibiotics; ampicillin, penicillin, ceftriaxone and ceftazidime and also highlights the importance of kleibsiella and Staphylococcus aureus as principal organism responsible for neonatal sepsis in tertiary care settings.

Enterococcal Urinary Tract Infections – An Evolving Trend with Changing Antimicrobial Resistance Patterns

Introduction: Urinary tract infections (UTI) are the most common infections encountered both in the community as well as in hospitalised patients. Enterococcus, which was once considered auropathogen of lower importance, is assuming importance as pathological agent in health care associated as well as community-acquired UTI for the last two to three decades. The aim of the present study was to evaluate the prevalence of enterococcal UTI to see its evolving trend and to study the changing antimicrobial resistance patterns in these isolates. Methods: Mid-stream urine samples of both inpatients and outpatients were collected over a period of 4 years from January 2011 to December 2014 and were processed by standard microbiological techniques. All the patients who had culture-proven enterococcal UTI were included in the study, whereas as urine samples showing other isolates like Escherichia coli, Klebsiella were excluded from the study. The isolates were further tested for antimicrobial susceptibility by disc diffusion method according to the Clinical Laboratory Standard Institute guidelines. Results: The present study analysed the urine samples showing enterococcal growth in cultures. Of the 332 patients having culture-proven UTI, 32 showed enterococcal infections in the year 2011 (about 10% of the positive samples). In 2012 and 2013, patients with enterococcal UTI were 42 and 56 out of a total of 300 and 351 positive samples, respectively. In the year 2014, enterococcus was isolated from 64 patients out of a total of 337 positive samples (19% of the total positive samples). Thus, there was an increasing trend in enterococcal UTI over the years. The study further showed that the females and the hospitalised patients were more vulnerable to enterococcal UTI. An increase in resistance to the commonly used antibiotics was found. Of the various antimicrobials tested, Enterococci showed the highest increase in resistance to Penicillin, Ampicillin, Amoxicillin clavulanate and Ciprofloxacin and an intermediate increase in resistance to Amikacin and Nitrofurantoin. The isolates showed the lowest increase in resistance to Teicoplanin, Vancomycin and Linezolid. Conclusion: The evolving epidemiology of UTI should be kept in mind while treating UTI, especially those with initial treatment failures. Antibiotic drug resistance has become a major threat because of misuse of drugs. This demands antimicrobial stewardship in hospitals and also institution of guidelines for empiric therapy where cultures are not available. This will help in better patient care, management and limit the spread of resistant strains.

Bacteriological trends and antibiotic susceptibility patterns of clinical isolates at Government Cancer Hospital, Marathwada.

Preventing and starting early treatment of infections in patients whose immunity system is weak due to malignancies can reduce mortality. Since our hospital is a newly constructed one, this study aimed to determine microbial and antibiotic resistance patterns in clinical samples of patients with cancer at our center to start early treatment before the results of clinical tests are known. The study was carried out in the Department of Microbiology, Government Cancer Hospital during the period from January 2016 to December 2016. A total 170 clinical samples (urine, blood, sputum, pus, etc.) were collected and processed for culture, identification as per standard recommended procedures and antibiotic susceptibility testing were carried out on isolates as per Clinical Laboratory Standard Institute guidelines. A total of 170 specimens were cultured. Escherichia coli, Acinetobacter spp. , Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa were most commonly encountered. A high level of resistance to various antibiotics was noted among Gram-negative bacteria. Resistance among Gram-positive was not acute. The present study reveals microbiological profile in patients attending our hospital. Regular surveillance helps in implementing better therapeutic strategies to reduce morbidity and mortality associated in patients in health-care facility.

GyrA ser83 and ParC trp106 Mutations in Salmonella enterica Serovar Typhi Isolated from Typhoid Fever Patients in Tertiary Care Hospital.

Typhoid fever is endemic in India and other developing countries, causing major public health problems with high morbidity and mortality. The resistance of Salmonella enterica serovar Typhi (S. Typhi) towards commonly prescribed antimicrobials is increasing in developing countries. However, there have been several reports of the therapeutic failure of fluoroquinolones in patients with Salmonella infection. Resistance to quinolones/ fluoroquinolones commonly arises due to target site mutation. The present study was planned to analyze mutation in Quinolone Resistance Determining Region (QRDR) of quinolone resistant Salmonella isolates. A total of 133 S. Typhi isolates (blood (n = 131), stool (n=1) and bone marrow aspirate (n=1)) from tertiary care hospitals in Chennai and Puducherry, were included in this study. Minimum Inhibitory Concentrations (MIC) were carried out according to the Clinical Laboratory Standard Institute (CLSI)guidelines 2014. Mutations in gyrA and parC genes were analyzed by PCR-RFLP (Restriction Fragment Length Polymorphism) method followed by DNA sequencing. Of the 133 S. Typhi, 99.2% were resistant to nalidixic acid and 21% were resistant to ciprofloxacin by MIC method. 94% of isolates showed Ser 83 mutation in gyrA and 21.8% of isolates showed Trp106-Gly mutation in parC. Mutations in gyrA and parC genes are highly prevalent among Salmonella species. Irrational use of fluoroquinolones may increase the accumulation of mutations in the DNA gyrase and topoisomerase encoding genes, which lead to the emergence of high level fluoroquinolone-resistant Salmonella strains in future.

A prospective study to analyse antibiotic susceptibility pattern of Pseudomonas aeruginosa in a tertiary care hospital

Background: Pseudomonas aeruginosa , a gram-negative pathogen is commonly associated with nosocomial infections. Infections caused by P. aeruginosa can range from superficial skin infections to fulminant sepsis. Antimicrobial resistance is an area of prime concern in pseudomonal infections. The objective of the study was to evaluate and analyse the antibiotic susceptibility pattern of P. aeruginosa at a tertiary care hospital in South India. Methods: The study was carried out at Kasturba Medical College and Hospital, Manipal, India from January 2011 to December 2011. Ten different types of specimens were collected from patients who were culture positive for Pseudomonas aeruginosa . Antibiotic susceptibility was confirmed by disk diffusion technique on Muller-Hinton medium and was performed according to the Clinical Laboratory Standard Institute (CLSI) guidelines. Results: Out of 200 samples of P. aeruginosa 69.5% and 30.5% were from male and female patients respectively. Majority of the specimen from which P. aeruginosa was isolated consisted of sputum, pus and urine. Among the antimicrobial drugs tested, organism was most sensitive to carbapenems (77.5%), piperacillin-tazobactam (77%) and cefoperazone-sulbactam (72%). Resistance rates were high for fluoroquinolones (FQs) (43.5%), gentamicin (40.5%), tobramycin (40.5%), ticarcillin-clavulanic acid (39%) and aztreonam (38%) when compared to cefepime (31.5%), ceftazidime (32.5%), netilmicin (34.5%) and amikacin (35%). Conclusions: Carbapenems and piperacillin-tazobactam were the best antipseudomonal agents with highest sensitivity to P. aeruginosa . FQs, gentamicin and tobramycin were the least effective drugs against P. aeruginosa as monotherapy.

Bacteriological profile and antibiotic susceptibility patterns of clinical isolates in a tertiary care cancer center.

Introduction:This increased risk of bacterial infections in the cancer patient is further compounded by the rising trends of antibiotic resistance in commonly implicated organisms. In the Indian setting this is particularly true in case of Gram negative bacilli such as Escherichia coli, Klebsiella pneumoniae and Acinetobacter spp. Increasing resistance among Gram positive organisms is also a matter of concern. The aim of this study was to document the common organisms isolated from bacterial infections in cancer patients and describe their antibiotic susceptibilities.Methods:We conducted a 6 month study of all isolates from blood, urine, skin/soft tissue and respiratory samples of patients received from medical and surgical oncology units in our hospital. All samples were processed as per standard microbiology laboratory operating procedures. Isolates were identified to species level and susceptibility tests were performed as per Clinical Laboratory Standards Institute (CLSI) guidelines -2012.Results:A total of 285 specimens from medical oncology (114) and surgical oncology services (171) were cultured. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Acinetobacter spp. were most commonly encountered. More than half of the Acinetobacter strains were resistant to carbapenems. Resistance in Klebsiella pneumoniae to cephalosporins, fluoroquinolones and carbapenems was >50%. Of the Staphylococcus aureus isolates 41.67% were methicillin resistant.Conclusion:There is, in general, a high level of antibiotic resistance among gram negative bacilli, particularly E. coli, Klebsiella pneumoniae and Acinetobacter spp. Resistance among Gram positives is not as acute, although the MRSA incidence is increasing.

ESBL producing Pseudomonas aeruginosa in clinical specimens: Is it a scary nightmare or paper tiger?

Background: Pseudomonas aeruginosa well known as opportunistic pathogen, has been implicated in life threatening nosocomial infections in recent years. This can be attributable to acquired resistance by plasmid mediated different types of extended spectrum beta lactamases(ESBL). The present study was undertaken to detect the ESBL production of Pseudomonas aeruginosastrains and analyze their susceptibility pattern. Methods: Various clinical specimens received in our laboratory were processed and Pseudomonas aeruginosa was identified as per standard microbiological procedure. A total of 132 clinical isolates of Pseudomonas aeruginosa identified during the study period were included in the study. All isolates were subjected for ESBL screening test. Potential ESBL producer was then subjected for ESBL Phenotypic confirmatory test –Disc Diffusion method(PCDDT). Antimicrobial susceptibility test was performed by Kirby – Bauer disc diffusion method on all confirmed isolates by PCDDT method as per Clinical Laboratory Standard Institute (CLSI 2016) guidelines. Results: By phenotypic confirmatory method, the frequency of occurrence of ESBL among the isolates identified was 21.96% (n = 29).The highest number of ESBL producers was obtained from urine samples(27.7%) followed by respiratory infection (23.68%) and wound infection (22.95%). In-vitro susceptibility of ESBL producers revealed high level of resistance to third generation cephalosporin. Low resistance was observed to Imipenem (3.4%) and Piperacillin – Tazobactam (13.79%). Conclusion: Our study highlights the unique challenge imposed by Pseudomonas aeruginosa as the therapeutic choices are limited by ESBL production. To overcome this issue, we recommend routine ESBL detection and surveillance of antibiotic resistance in hospital settings. Keywords: Pseudomonas aeruginosa, ESBL, Third generation cephalosporins, Imipenem, Urine, ESBL Screening test

Antimicrobial susceptibility of bacteria isolated from neonatal foal samples submitted to a New Zealand veterinary pathology laboratory (2004 to 2013)

AIMS: To describe antimicrobial susceptibility, and identify antimicrobial resistance (AMR), in bacteria isolated from New Zealand foals.METHODS: A database search was performed of submissions to a veterinary pathology laboratory between April 2004 and December 2013 for bacterial culture of samples from foals <3 weeks of age. Culture and susceptibility results were compiled with demographic information. Susceptibility results were as defined for the Kirby-Bauer disk diffusion susceptibility test based on Clinical Laboratory Standards Institute guidelines. Multi-drug resistance (MDR) was defined as non-susceptibility to ≥3 of a panel of antimicrobials (ceftiofur, enrofloxaxin, gentamicin, penicillin, tetracycline, trimethoprim-sulfonamide); penicillin susceptibility was not included for Gram-negative isolates.RESULTS: Submissions from 102 foals were examined, and 127 bacterial isolates were cultured from 64 (63%) foals. Of the 127 isolates, 32 (25%) were Streptococcus spp., 30 (24%) were Staphylococcus spp., 12 (10%) were Enterococcus spp. and 26 (21%) were Escherichia coli. Of 83 Gram-positive isolates, 57 (69%) were susceptible to penicillin. Over all isolates, 92/126 (73%) were susceptible to gentamicin and 117/126 (93%) to enrofloxacin; 62/82 (76%) of Gram-positive, and 22/42 (52%) of Gram-negative bacteria were susceptible to ceftiofur; 53/81 (65%) of Gram-positive, and 23/44 (52%) of Gram-negative bacteria were susceptible to tetracycline; 59/82 (72%) of Gram-positive, and 23/44 (43%) of Gram-negative bacteria were susceptible to trimethoprim-sulfonamide. Of 126 isolates, 33 (26%) had MDR; >1 isolate with MDR was cultured from 24/64 (38%) foals, and ≥2 isolates with MDR were recovered from 8/64 (13%) foals.CONCLUSIONS: Multi-drug resistance, including resistance to commonly used antimicrobials, was found in bacterial isolates from foals in New Zealand.CLINICAL RELEVANCE: The results of this study are of concern from a treatment perspective as they indicate a potential for antimicrobial treatment failure. For future surveillance of AMR and the creation of national guidelines, it is important to record more data on samples submitted for bacterial culture.