Risk factors for fecal carriage of carbapenemase producing Enterobacteriaceae among intensive care unit patients from a tertiary care center in India.

BACKGROUND: Resistance amongst the commensal flora is a serious threat because a very highly populated ecosystem like the gut, may at a later stage, be a source of extra intestinal infections, resistant strains may spread to other host or transfer genetic resistance element to other members of micro-biota including pathogens. This study was carried out to assess fecal colonization by carbapenemase producing Enterobacteriaceae (CPE) and associated risk factors among 100 patients admitted to intensive care unit (ICU). The phenotypic and molecular characterizations of CPE were also included. RESULTS: Colonization with CPE was observed in 6.6 % (8/122) controls. Among ICU patients, fecal carriage of CPE was significantly higher on day 4 (D4) (22 %) as compared to day 1 (D1) (11 %) (p value 0.002). The carbapenemase genes detected included OXA- 48, 181, KPC and NDM-1 with NDM-1 being the predominant carbapenemase in both ICU D1 and D4. Among the 50 CPE isolates, 8 (16 %) were susceptible to meropenem and imipenem (Minimum inhibitory concentration; MIC ≤ 1 mg/L) and all were susceptible to colistin (MIC range 0.125 - 1 mg/L) and tigecycline (MIC range 0.06- 1.5 mg/L). The risk factors associated with CPE carriage were duration of ICU stay, use of ventilator and aminoglycosides. CONCLUSIONS: Prior colonization with CPE could result in their influx and spread in ICU, challenging infection control measures. Exposure to ICU further increases risk of colonization with diverse carbapenemase-producing Enterobacteriaceae. Gut colonization with these strains may be a source of endogenous infection and horizontal transfer of these genes in future.

Clinically and microbiologically derived azithromycin susceptibility breakpoints for Salmonella enterica serovars Typhi and Paratyphi A.

Azithromycin is an effective treatment for uncomplicated infections with Salmonella enterica serovar Typhi and serovar Paratyphi A (enteric fever), but there are no clinically validated MIC and disk zone size interpretative guidelines. We studied individual patient data from three randomized controlled trials (RCTs) of antimicrobial treatment in enteric fever in Vietnam, with azithromycin used in one treatment arm, to determine the relationship between azithromycin treatment response and the azithromycin MIC of the infecting isolate. We additionally compared the azithromycin MIC and the disk susceptibility zone sizes of 1,640 S. Typhi and S. Paratyphi A clinical isolates collected from seven Asian countries. In the RCTs, 214 patients who were treated with azithromycin at a dose of 10 to 20 mg/ml for 5 to 7 days were analyzed. Treatment was successful in 195 of 214 (91%) patients, with no significant difference in response (cure rate, fever clearance time) with MICs ranging from 4 to 16 µg/ml. The proportion of Asian enteric fever isolates with an MIC of ≤ 16 µg/ml was 1,452/1,460 (99.5%; 95% confidence interval [CI], 98.9 to 99.7) for S. Typhi and 207/240 (86.3%; 95% CI, 81.2 to 90.3) (P < 0.001) for S. Paratyphi A. A zone size of ≥ 13 mm to a 5-µg azithromycin disk identified S. Typhi isolates with an MIC of ≤ 16 µg/ml with a sensitivity of 99.7%. An azithromycin MIC of ≤ 16 µg/ml or disk inhibition zone size of ≥ 13 mm enabled the detection of susceptible S. Typhi isolates that respond to azithromycin treatment. Further work is needed to define the response to treatment in S. Typhi isolates with an azithromycin MIC of >16 µg/ml and to determine MIC and disk breakpoints for S. Paratyphi A.

Phenotypic and molecular characterization of clinical isolates of Acinetobacter baumannii isolated from Delhi, India.

BACKGROUND: Acinetobacter has gained importance as a multi-drug resistant and hence a difficult to treat pathogen. This study was done to characterize our isolates with respect to drug resistance and presence of beta-lactamases which is a major mechanism of resistance and to type using RAPD and MLST so that comparison of our clones can be made with the existing international clones. METHODS: 100 isolates recovered from clinical samples from two hospitals in Delhi were tested for their susceptibility against major groups of antimicrobials. The resistant isolates were screened and confirmed phenotypically for presence of ESBL, MBL and AmpC and MBLs also by PCR. The isolates were typed by RAPD and MLST. RESULTS: Out of the 100 isolates, 91, 78 and 2 % were MDR, XDR and PDR respectively. 97, 100 and 85 were screen positive for ESBL, AmpC and MBL respectively. Of these, 38.1 % were confirmed phenotypically to produce ESBL, 99 % produced AmpC and 29.4 % produced MBL comprising of GIM, VIM, SIM and IMP. MLST showed known STs 110, 188, 146, 69, 103, 108 and 194. Eight new STs were encountered. The RAPD showed a high degree of genetic variability among the isolates. CONCLUSION: Majority of our isolates were MDR, producing one or more types of beta-lactamases. We encountered drug resistant international clones by MLST which are found in other continents there by confirming their spread to Indian sub continent. No data on ST types of other Indian isolates is available in the MLST database and hence comparison is not possible.

Community acquisition of ß-lactamase producing Enterobacteriaceae in neonatal gut.

BACKGROUND: Commensal flora constitutes a reservoir of antibiotic resistance. The increasing variety of ß-lactamases and the emergence of Carbapenem resistant Enterobacteriaceae (CRE) in community, raise concerns regarding efficacy of ß-lactams. It is important to know the exact load of antibiotic resistance in the absence of any antibiotic selection pressure including via food and water.In the present study gut colonization in neonates with no direct antibiotic pressure was used as a model to evaluate ß-lactam resistance in the community. RESULTS: In this prospective study, 75 healthy, vaginally delivered, antibiotic naive, breast fed neonates were studied for gut colonization by Extended spectrum ß-lactamases (ESBL), AmpC ß-lactamases hyperproducing Enterobacteriaceae and CRE on day 0, 21 and 60. Total 267 Enterobacteriaceae were isolated and E.coli was the predominant flora. ESBL, AmpC and coproduction was seen in 20.6%, 19.9% and 11.2% isolates respectively. ESBL carriage increased threefold from day 1 to 60 showing predominance of CTX-M group 15 (82.5%), ampC genes were heterogeneous. Colonization with CRE was rare, only one baby harboured Enterobacter sp positive for kpc-2. The reservoirs for these genes are likely to be mother and the environment. CONCLUSIONS: Data strongly suggests that in absence of any antibiotic pressure there is tremendous load of antibiotic resistance to ß-lactam drugs. Wide spread presence of ESBL and AmpC can drive rapid emergence and dissemination of CRE. This is the first report from India which depicts the smaller picture of true antibiotic pressure present in the Indian community.

Bacteraemic Haemophilus influenzae type B pneumonia complicated with empyema--report of a case and review of literature.

A case of bacteraemic pneumonia complicated with pleural empyema due to Haemophilus influenzae type b is reported in a one-year old previously healthy child who had apparently no other associated medical condition. The organism was isolated from both the pleural fluid aspirate and blood of the patient with pneumonia. She was successfully treated with parenteral ampicillin and chloramphenicol alongwith intercostal chest tube drainage. The case is notable because it adds to the existing disease spectrum of invasive Hib diseases and brings awareness to the existing burden of the disease in Asia. In addition, it reflects the urgent need to include Hib vaccine in the current immunization program in India.

Genetic characterization of Chikungunya virus from New Delhi reveal emergence of a new molecular signature in Indian isolates.

BACKGROUND: Chikungunya (CHIK) is currently endemic in South and Central India and exist as co-infections with dengue in Northern India. In 2010, New Delhi witnessed an outbreak of CHIK in the months October-December. This was the first incidence of a dominant CHIK outbreak in Delhi and prompted us to characterize the Delhi virus strains. We have also investigated the evolution of CHIK spread in India. FINDINGS: Clinical samples were subjected to RT-PCR to detect CHIK viral RNA. The PCR amplified products were sequenced and the resulting sequences were genetically analyzed. Phylogenetic analysis based on partial sequences of the structural proteins E1 and E2 revealed that the viruses in the latest outbreak exhibited ECSA lineage. Two novel mutations, E1 K211E and E2 V264A were observed in all Delhi isolates. In addition, CHIKV sequences from eight states in India were analyzed along with Delhi sequences to map the genetic diversity of CHIKV within the country. Estimates of average evolutionary divergence within states showed varying divergence among the sequences both within the states and between the states. We identified distinct molecular signatures of the different genotypes of CHIKV revealing emergence of a new signature in the New Delhi clade. Statistical analyses and construction of evolutionary path of the virus within the country revealed gradual spread of one specific strain all over the country. CONCLUSION: This study has identified unique mutations in the E1 and E2 genes and has revealed the presence of ancestral CHIKV population with maximum diversity circulating in Maharashtra. The study has further revealed the trend of CHIK spread in India since its first report in 1963 and its subsequent reappearance in 2005.

Resistance spectrum of antimicrobial among community-acquired uropathogens in a tertiary care hospital of Delhi.

This study was carried out to provide information regarding resistance pattern of community acquired uropathogens in a tertiary care hospital. A retrospective analysis of culture proven urine isolates was carried out over a period of 1 year (Jan-Dec 2009). Antimicrobial susceptibility testing was done by Kirby Bauer disc diffusion method and results were interpreted in accordance with the recommendation of clinical and laboratory standard institute (CLSI). Out of the total 10698 mid-stream urine samples received from suspected cases of urinary tract infection (UTI), 2124 (19.9%) were culture proven UTI cases. Escherichia coli was the most common isolate (54.6%) followed by Staphylococcus aureus (14.7%). Among gram-negative organism (E. coli) showed high resistance to amoxiclavulanate (91.7%) & cefodroxyl (73.1%). Quinolones have shown resistance among majority of the pathogens (ranging from 30-90%). Staph aureus and enterococcus species were found to be resistant to ampicillin (84.4% and 64.5%) and norfloxacin (69% and 58.7%). Nitrofurantoin may be considered as a first line agent for empiric treatment of uncomplicated out patients. Drug resistance is a common problem and need is for judicious use of antimicrobial agents after laboratory monitoring.

Minimum inhibitory concentration of carbapenems and tigecycline against Salmonella spp.

Antimicrobial resistance in Salmonella spp. is of grave concern, more so in quinolone-resistant and extended-spectrum beta-lactamase (ESBL)-producing isolates that cause complicated infections. The MIC of azithromycin, ciprofloxacin, cefixime, cefepime, ceftriaxone, gatifloxacin, imipenem, levofloxacin, meropenem and ofloxacin (E-test strip) and tigecycline and faropenem (agar dilution) against 210 Salmonella spp. was determined. MIC(90) (defined as the antimicrobial concentration that inhibited growth of 90 % of the strains) of the carbapenems (imipenem and meropenem) for Salmonella Typhi and Salmonella Paratyphi A was 0.064 microg ml(-1). MIC(90) of faropenem was 0.25 microg ml(-1) for S. Typhi, S. Paratyphi A and Salmonella Typhimurium. The MIC(90) of azithromycin for all Salmonella spp. ranged from 8 to 16 microg ml(-1). Tigecycline showed an MIC(90) of 2 microg ml(-1) for S. Typhi, 1 microg ml(-1) for S. Paratyphi A and 4 microg ml(-1) for S. Typhimurium. We concluded that tigecycline and the carbapenems are likely to have roles in the final stage of treatment of quinolone-resistant and ESBL-producing multidrug-resistant salmonellae.

In vitro evaluation of a new cefixime-clavulanic acid combination for gram-negative bacteria.

The study was conducted to evaluate a new cefixime-clavulanic acid combination for in vitro susceptibility towards gram-negative bacteria. A total of 220 isolates of Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeroginosa, Acinetobacter spp, Salmonella enterica serovar Typhi and Salmonella enterica serovar Typhimurium were included in the study. The isolates were tested for susceptibility towards the new combination antimicrobial molecule cefixime with clavulanic acid by disk diffusion and Epsilometer strip (E-strip) Minimum Inhibitary Concentration (MIC) method. Of the 101 E. coli and K. pneumoniae isolates, 62.4% were found to be extended spectrum beta-lactamase (ESBL) producers. Almost half of these were from the community and 55.6% were hospital isolates. Of the ESBL isolates, 19% were AmpC (cephalosporinases that are poorly inhibited by beta lactamase inhibitor) producers while the remaining 81% were non AmpC ESBL producers. The AmpC producers were resistant to both cefixime and the combination, while the non-AmpC producers were sensitive to the combination. The addition of clavulanate to cefixime did not improve the sensitivities of P. aeruginosa and Acinetobacter isolates. There were no ESBL isolates among the S. Typhi isolates, all of which were sensitive to cefixime. Of the S. Typhimurium, 88.9% were ESBL producers and all of these were resistant to cefixime but sensitive to the combination. The combination of cefixime with clavulanic acid offers the advantage of oral administration and appears to be a viable option for the treatment of uncomplicated community acquired infections caused by non-AmpC ESBL producing gram-negative bacteria.

Current scenario of cryptococcosis and antifungal susceptibility pattern in India: a cause for reappraisal.

This study analysed the spectrum, antifungal susceptibility pattern, clinical course and molecular epidemiology of cryptococcosis. Four hundred and thirty-nine samples obtained from 378 meningitis patients were processed by standard procedures. Minimum inhibitory concentration (MIC) of fluconazole and amphotericin B for the isolates was tested by broth micro dilution and by E-strip method. Molecular analysis by random amplified polymorphic DNA-PCR of eight isolates was performed using M13 primer. Cryptococcosis was diagnosed in 35 patients [HIV-1 seropositive (19) and apparently immunocompetent (16)]. Cryptococcus neoformans var. neoformans (serotype A and D) was the predominant isolate on phenotypic identification. Three C. neoformans var. gattii were isolated from HIV-1 seropositive (2) and apparently immunocompetent (1) patients. MIC 90 for amphotericin B and fluconazole were 1 and 8 mug ml(-1) respectively. On RAPD-PCR, less diversity was seen among Indian isolates. AIDS remains the single most important risk factor for cryptococcosis. Rising MIC of the available induction and maintenance drugs is of grave concern. The DNA typing technique showed less diversity among Indian strains. Routine surveillance and application of molecular typing methods are crucial to know the baseline and existing pattern of cryptococcosis.

Neurocysticercosis in a north Indian hospital.

In endemic regions, neurocysticercosis (NCC) is the most commonly diagnosed parasitic disease of the central nervous system, and the most common cause of convulsions and hydrocephalus in adults. During January 2000-December 2006, serum samples collected from patients presenting with various manifestations with a clinical diagnosis of cysticercosis and/or relevant computed tomography findings were subjected to an enzyme-linked immunosorbent assay test for NCC. Anti-cysticercus antibodies were detected in 155 of the 1096 (14.1%) cases. Generalized seizure (33.9%) was the most common presenting symptom. Solitary lesion (74.2%) was the most common radiological finding. This study provides an assessment of the epidemiology of NCC in Delhi and stresses the need for its prevention.

Alarming rates of antimicrobial resistance and fungal sepsis in outborn neonates in North India.

BACKGROUND: There is a paucity of data on the epidemiology of sepsis in outborn neonates being referred to level-3 units in low- and middle-income countries (LMIC). The objective of the present study was to evaluate the prevalence of sepsis and outcomes of outborn neonates with sepsis, and to characterize the pathogen profile and antimicrobial resistance (AMR) patterns of common isolates in them. METHODS: In this prospective observational cohort study (2011-2015), a dedicated research team enrolled all neonates admitted to an outborn level-3 neonatal unit and followed them until discharge/death. Sepsis work-up including blood culture(s) was performed upon suspicion of sepsis. All the isolates were identified and tested for antimicrobial susceptibility. Gram-negative pathogens resistant to any three of the five antibiotic classes (extended-spectrum cephalosporins, carbapenems, aminoglycosides, fluoroquinolones, and piperacillin-tazobactam) were labeled multi-drug resistant. RESULTS: Of the total of 2588 neonates enrolled, culture positive sepsis and total sepsis-i.e. culture positive and/or culture negative sepsis-was diagnosed in 13.1% (95% CI 11.8% to 14.5%) and 54.7% (95% CI 52.8% to 56.6%), respectively. The case fatality rates were 23.4% and 11.0% in culture-positive and total sepsis, respectively. Sepsis accounted for two-thirds of total neonatal deaths (153/235, 63.0%). Bacterial isolates caused about three-fourths (296/401; 73.8%) of the infections. The two common pathogens-Klebsiella pneumoniae (n = 50, 12.5%) and Acinetobacter baumannii (n = 46, 11.5%)-showed high degree of multi-drug resistance (78.0% and 91.3%, respectively) and carbapenem resistance (84.0% and 91.3%, respectively). About a quarter of infections were caused by Candida spp. (n = 91; 22.7%); almost three-fourths (73.7%) of these infections occurred in neonates born at or after 32 weeks' gestation and about two-thirds (62.1%) in those weighing 1500 g or more at birth. CONCLUSIONS: In this large outborn cohort, we report high burden of sepsis, high prevalence of systemic fungal infections, and alarming rates of antimicrobial resistance among bacterial pathogens.

Ciprofloxacin-resistant Neisseria meningitidis, Delhi, India.

Decreased susceptibility of Neisseria meningitidis isolates to ciprofloxacin emerged from an outbreak in Delhi, India. Results of antimicrobial susceptibility testing of the meningococcal isolates to ciprofloxacin and further sequencing of DNA gyrase A quinolone-resistance-determining region confirmed the emergence of ciprofloxacin resistance in the outbreak.

In vitro activity of azithromycin, newer quinolones and cephalosporins in ciprofloxacin-resistant Salmonella causing enteric fever.

The therapeutic alternatives available for use against ciprofloxacin-resistant enteric fever isolates in an endemic area are limited. The antibiotics currently available are the quinolones, third-generation cephalosporins and conventional first-line drugs. In this study, the MICs of various newer drugs were determined for 31 ciprofloxacin-resistant enteric fever isolates (26 Salmonella enterica serovar Typhi and 5 S. enterica serovar Paratyphi A). MICs for ciprofloxacin, ofloxacin, gatifloxacin, levofloxacin, cefotaxime, cefixime, cefepime and azithromycin were determined using Etest strips and the agar dilution method. By Etest, all of the ciprofloxacin-resistant isolates had ciprofloxacin MICs >/=32 mug ml(-1). S. Typhi showed MIC(90) values of 0.50, 0.25 and 0.38 mug ml(-1) for cefixime, cefotaxime and cefepime, respectively. For the cephalosporins, a negligible difference in MIC(90) and MIC(50) values for S. Typhi and S. Paratyphi A was observed. A single isolate of S. Typhi showed a high azithromycin MIC of 64 mug ml(-1). The MIC(90) value for azithromycin in S. Typhi and S. Paratyphi was 24 mug ml(-1). Gatifloxacin demonstrated lower resistance (80.8 %) compared with the other quinolones (92-100 %) in S. Typhi. The rise in MIC levels of these antimicrobials is a matter for serious concern.

Antimicrobial susceptibility patterns of Salmonella enterica serotype typhi in eastern Nepal.

The aim of the present study was to evaluate antimicrobial susceptibility patterns with special reference to multidrug resistance, susceptibility to ciprofloxacin, and bacteriophage typing of Salmonella enterica serotype Typhi isolated from blood sent for culture in a tertiary-care teaching hospital in eastern Nepal during January 2000-December 2004. In total, 132 strains of S. enterica Typhi, isolated from 2,568 blood culture samples collected from cases of suspected enteric fever, were tested for susceptibility to commonly-used antimicrobials by the disc-diffusion method. There were 35 multidrug-resistant strains. None of the isolates were resistant to ciprofloxacin. Of 52 isolates tested for minimum inhibitory concentration (MIC) of ciprofloxacin, 36 (69.23%) showed reduced susceptibility (MIC >0.25 mg/L). Of 112 strains tested for nalidixic acid susceptibility, 86 (76%) were resistant. Strains with reduced susceptibility to ciprofloxacin and resistance to nalidixic acid could be correlated. The commonest phage type was El. Nalidixic acid susceptibility could be a useful screening test for the detection of decreased susceptibility of S. Typhi to ciprofloxacin, a drug which is commonly used even for minor ailments in this area.

Characterization of Vancomycin Resistant Enterococci in Hospitalized Patients and Role of Gut Colonization.

INTRODUCTION: Enterococci are part of the normal intestinal flora and have been recognized as important human pathogens. Vancomycin Resistant Enterococci (VRE) are global threat as this resistance is transmissible and also poses a challenge for infection control. AIM: This study was undertaken to study phenotypic and genotypic characteristics of VRE from clinically significant infections among hospitalized patients and their association with gut colonization. MATERIALS AND METHODS: Clinically significant isolates of enterococci (n=250) were studied. Species confirmation was done by Polymerase Chain Reaction (PCR). Minimum Inhibitory Concentration (MIC) for vancomycin was determined by E-test. PCR for VanA, VanB and VanC1 gene was done for genotypic characterization. MIC for teicoplanin, linezolid, tigecycline, daptomycin and quinupristin-dalfopristin was determined by E test. Patients with VRE infection were screened for gut colonization using vancomycin screen agar (6 µg/mL). Continuous data was analysed using the Student's t-test. Categorical data was assessed using Pearson's Chi-square test. A value of p ≤ 0.05 was considered statistically significant. RESULTS: There was good correlation between the phenotypic and genotypic methods used for species identification and detection of vancomycin resistance. E. faecium (162, 64.8%) was most common followed by E. faecalis (82, 32.84%) and E. gallinarum (6, 2.4%). Overall higher resistance was observed among E. faecium. Vancomycin MIC ≥ 2 µg/mL was noted in 63 (25.2%) isolates. Fifty seven isolates showed presence of vanA and vanC1 was detected in six isolates of E. gallinarum. Isolates with VanB genotype was not detected in the present study. MIC50 (µg/mL) for teicoplanin, linezolid, tigecycline, daptomycin and quinupristin-dalfopristrin was 24, 0.75, 0.064, 2 and 0.064 respectively. Resistance to linezolid (1, 1.6%) and tigecycline (2, 3.2%) was rare. Majority (33/47, 70.2%) patients with clinically significant VRE infection showed gut colonization. CONCLUSION: Vancomycin resistance among enterococci is emerging. Emergence of tigecycline and linezolid resistance is also posing a challenge for clinicians. Thus, further investigations are warranted to control vancomycin resistance among pathogens.

Molecular Subtyping of Salmonella enterica Serovar Typhi by Pulsed-Field Gel Electrophoresis and Multiple-Locus Variable-Number Tandem-Repeat Analysis in India: Their Association with Antimicrobial Resistance Profiles.

Molecular subtyping and DNA sequencing-based methods, which are commonly used for discriminating Salmonella enterica serovar Typhi (S. Typhi) isolates, lead to improved molecular epidemiological investigations for prevention and control of typhoid fever. We obtained S. Typhi blood isolates (n = 66) from India during 2007-14 for molecular subtyping by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) in association with antibiotic resistance profiles. Genotypic diversity was observed more by MLVA (Simpson's index of diversity, D value = 0.997) than PFGE (D value = 0.864). Two prevalent pulsotypes containing nalidixic acid-resistant (NALR) and NALR-ciprofloxacin-resistant (CIPR) S. Typhi isolates circulated in India. Multidrug-resistant (MDR), NALR-CIPR, and most NALR isolates were found to be clonal by PFGE. MLVA could differentiate the clonal isolates. Most of the MDR and NALR-CIPR isolates showed variation in single or double VNTR loci, whereas NALR isolates varied in more than 2 loci, reflecting higher genetic diversity among the NALR isolates. Of the 6 VNTR loci, TR4,699 (D value = 0.838) and Sal02 (D value = 0.890) loci played important roles as MLVA cluster-supporting alleles. The rapid turnaround time and high-level discriminatory power of MLVA may be useful for tracking and controlling the transmission of S. Typhi isolates during epidemiological investigations.

Molecular typing of Salmonella enterica serotype Worthington isolates from infantile diarrhoea.

BACKGROUND AND OBJECTIVES: Salmonella Worthington has been known to be a causative agent for childhood diarrhoea. There is a paucity of information on the molecular relatedness of the strains isolated in various hospitals in India. The present study was carried out to attempt molecular typing of a cluster of Salmonella Worthington isolates obtained from cases of infantile diarrhoea during a six month period, from a tertiary care paediatric hospital in Delhi, India. METHODS: Nine isolates of S. Worthington obtained from faecal samples of infants suffering from diarrhoea during October 2001 to March 2002, were identified by the conventional biochemical methods and by serotyping. The antimicrobial susceptibility was determined by the disk diffusion method. Molecular typing was done by ribotyping. RESULTS: Eight patients were admitted to 3 different wards of the hospital and one was an outpatient. Four patients including the first patient visited the hospital with diarrhoea as the presenting symptom while five developed diarrhoea after admission. Stool microscopy showed no specific findings. Salmonella Worthington was isolated from stool cultures of these patients. Repeated cultures of the common drinking water source of the hospital and the milk supplied to children from central kitchen were negative for known pathogens. All S. Worthington isolates were resistant to all the beta-lactams tested including third generation cephalosporins. Eight isolates were sensitive to furazolidone and 6 to ciprofloxacin. Molecular characterization by ribotyping revealed four different clones. INTERPRETATION AND CONCLUSION: As four different ribotypes of the isolated Salmonella Worthington isolates were identified, it was clear that there was no single source of infection.

Resistance to erythromycin and rising penicillin MIC in Streptococcus pyogenes in India.

There has been worldwide resurgence in the incidence of Streptococcus pyogenes infection and its sequelae. S. pyogenes remains uniformly susceptible to penicillin, and it is speculated that its minimum inhibitory concentration (MIC) has not changed during the past 70 years. The purpose of the present study was to determine the occurrence and pattern of resistance to penicillin and erythromycin amongst clinical isolates of S. pyogenes. A total of 34 clinical strains of S. pyogenes were identified by standard procedures. Antimicrobial susceptibility was analyzed by the Kirby-Bauer method of disk diffusion, and the E-test method was used to determine the MIC to penicillin and erythromycin. All the strains were sensitive to penicillin, clindamycin and vancomycin on disk diffusion. Ten (29.4%) strains were resistant to erythromycin. The pattern of macrolide resistance observed was M type. By the E-test method, 7 (20.6%) strains were penicillin nonsusceptible and 6 (17.6%) were erythromycin resistant. We concluded that surveillance of its susceptibility pattern is crucial to monitoring the development of antibiotic resistance in S. pyogenes.