Prospective study estimating healthcare associated infections in a paediatric hemato-oncology unit of a tertiary care hospital in north India.

Background & objectives: Healthcare associated infections (HAIs) are responsible for morbidity and mortality among immunocompromised and critically ill patients. We undertook this study to estimate the burden of HAIs in the paediatric cancer patients in a tertiary care hospital in north India. Methods: This prospective, observational study, based on active surveillance for a period of 11 months was undertaken in a 4-bedded isolated, cubicle for paediatric cancer patients. Patients who stayed in the cubicle for ≥48 h, were followed prospectively for the development of HAIs. Results: Of the 138 patients, 13 developed 14 episodes of HAIs during the study period. Patient-days calculated were 1273 days. Crude infection rate (CIR) and incidence density (ID) of all HAIs were 9.4/100 patients and 11/1000 patient-days, respectively. Of the 14 episodes of HAIs, seven (50%) were of blood stream infections (HA-BSI), five (36%) of pneumonia (HAP) and two (14%) urinary tract infections (HA-UTI). The CIRs of HA-BSI, HAP and HA-UTI were 5.1, 3.6 and 1.4/100 patients, respectively. The corresponding IDs were 5.5, 3.9 and 1.6/1000 patient-days, respectively. Mean length of stay was significantly higher in patients who developed an HAI [13.8 (range 7-30), median (Interquartile range) 12 (11-14)] vs 7.5 days [range 2-28, median (interquartile range) 7 (5-9); P<0.0001]. Also mortality was significantly higher in patients who developed an HAI [23% (3/13) vs 3% (4/125), P<0.05]. Interpretation & conclusions: The incidence of HAIs in the paediatric cancer patients in the study was 11/1000 patient days, of which HA-BSIs were the commonest. HAIs were associated with an increase in morbidity and mortality amongst this high risk patient population.

Characterization of nasopharyngeal isolates of type b Haemophilus influenzae from Delhi.

Background & objectives: Haemophilus influenzae is an important cause of mortality and morbidity among young children in developing countries. Increasing incidence of antibiotic resistance especially production of extended spectrum beta lactamase (ESBL) has made treatment and management of H. influenzae infection more difficult. Nasopharyngeal H. influenzae isolates are excellent surrogate for determination of antibiotic resistance prevalent among invasive H. influenzae isolates. In this study, we characterized nasopharyngeal H. influenzae isolates obtained from healthy school going children in Delhi. Methods: Nasopharyngeal H. influenzae isolates were collected from healthy school going children and subjected to serotyping, fimbrial typing and antibiogram profiling. ESBL production was recorded using phenotypic as well as molecular methods. Multi locus sequence typing (MLST) of 13 representative nasopharyngeal H. influenzae isolates was performed as per guidelines. Results: A significant proportion (26 of 80, 32.5%) of nasopharyngeal isolates of H. influenzae were identified as serotype b. Fimbrial gene (hifA) was detected in 23 (28.75%) isolates. Resistance against commonly prescribed antibiotics (Amp, Tet, Chloro, Septran, Cephalexin) were observed to be high among the nasopharyngeal commensal H. influenzae. Extended spectrum beta lactamase (ESBL) production was observed in a five (6.25%) isolates by both double disk diffusion and molecular typing. MLST identified several novel alleles as well as novel sequence types. Interpretation & conclusions: Our findings showed high resistance against common antibiotics and detection of ESBL in nasopharyngeal H. influenzae isolates collected from normal healthy school going children in Delhi. Detection of H. influenzae type b capsular gene and the presence of fimbrial gene (hif A) suggest virulence potential of these isolates. Discovery of novel alleles and presence of new sequence types (STs) among nasopharyngeal H. influenzae isolates may suggest wider genetic diversity.

Occurrence of TEM & SHV gene in extended spectrum beta-lactamases (ESBLs) producing Klebsiella sp. isolated from a tertiary care hospital.

BACKGROUND & OBJECTIVE: Extended-spectrum beta-lactamases (ESBLs) are rapidly evolving group of beta-lactamase enzymes produced by the Gram negative bacteria. These enzymes have been derived from TEM and SHV genes by mutations and have been well described in Klebsiella pneumoniae. Information on molecular types of ESBL positive Klebsiella sp. is lacking from India. We therefore undertook this study to look for the TEM and SHV genes in ESBL positive Klebsiella sp. isolated from the patients admitted to a tertiary care hospital in north India. METHODS: A total of 204 multidrug-resistant isolates of Klebsiellae obtained from clinical samples; blood (n=108), urine (n=15), pus (n=2) and sputum (n=79) were obtained and screened for resistance to 3rd generation cephalosporins (3GC). The ESBL status was determined by double disk diffusion test (DDDT) and further by ESBL E-test. Multiplex PCR specific for TEM and SHV genes was performed to distinguish four different genotypes: TEM-positive, SHV-positive, TEM- and SHV-positive and non-TEM non-SHV ESBL types. RESULTS: Eighty six per cent (175 of 204) of the isolates were found to be resistant to at least one of the 3GCs, of which 97.1 per cent (170) of Klebsiella sp. isolates were confirmed to be positive for ESBL. Of these 170 isolates, 95 were randomly selected for PCR of TEM and SHV genes. Isolates having both TEM and SHV genes were common (67.3%) whereas only 20 per cent isolates possessed TEM gene and 8.4 per cent SHV gene alone. INTERPRETATION & CONCLUSION: Our findings showed that the majority of the ESBL positive clinical isolates of Klebsiella sp. carried both TEM and SHV genes followed by TEM alone. Such studies need to be done in various geographical regions of the country to know about the prevalent genotypes for better management of infection.

Profile of bacterial isolates from suspected cases of infective endocarditis (IE): a retrospective study in a north Indian tertiary care hospital.

Infective Endocarditis (IE) is an emerging infection of the twenty-first century. This chronic Infection is mainly caused by bacteria, although fungi can also be associated with it. It is Important to know the profile of bacteria causing IE in a given region so as to suggest the empirical therapy for this serious illness. Blood culture isolates of clinically diagnosed or suspected cases of IE admitted to various wards of the All India Institute of Medical Sciences were analyzed retrospectively from January 2000 to June 2004. Standard techniques were used for the isolation and identification of the bacteria. Our study has demonstrated the predominance of Gram-negative bacilli, especially, Acinetobacter species and Pseudomonas aeruginosa, which are notorious for antimicrobial resistance, as the aetiological agents of IE. Amongst Gram-positive cocci, Enterococci exhibiting HLAR comprised the predominant species. Methicillin resistance among staphylococcal strains in this Tertiary care hospital is adding to the therapeutic challenge in the management of this serious illness. Although antimicrobial treatment should not be delayed in such cases, we cannot undermine the importance of isolation and identification of the etiological agents and the determination of the antimicrobial susceptibility for the management of these life-threatening conditions as well as for the formulation of guidelines for empirical therapy of these cases.

Emerging resistance to carbapenems in a tertiary care hospital in north India.

BACKGROUND AND OBJECTIVES: Carbapenems are beta-lactam antibiotics, presently considered as most potent agents for treating multi-drug resistant Gram-negative bacilli infections. In India carbapenems available for use are meropenem and imipenem, introduced recently. Resistance to these has been reported in a few bacteria especially Pseudomonas spp. We therefore retrospectively evaluated the antibiotic susceptibility pattern to these agents amongst various clinical isolates in a tertiary care hospital in north India. METHODS: In this study Gram-negative bacterial pathogens isolated from clinical samples were tested for extended spectrum beta lactamase (ESBL) production. All ESBL positive bacteria were tested for meropenem and imipenem activity pattern using NCCLS guidelines. A total of 2626 consecutively isolated Gram-negative bacteria, which tested positive for ESBL production by the double disk diffusion method, were included. RESULTS: The different bacteria isolated were Pseudomonas spp. 759, Acinetobacter spp. 676, Escherichia coli 569, Klebsiella spp. 343, Enterobacter spp. 150, Citrobacter spp. 57 and Proteus spp. 72. Overall resistance to meropenem was more (22.16%) than imipenem (17.32%). Maximum resistance was seen in Pseudomonas spp. M(R) 37.6 per cent, I(R) 30 per cent. In isolates from intensive care units (ICU) resistance to carbapenems was significantly higher than non-ICU patients. INTERPRETATION AND CONCLUSION: Resistance to meropenem and imipenem was seen in various clinical isolates of Gram-negative ESBL-positive bacteria. There is a need to alarm our clinicians for judicious use of antibiotics.

Comparative in vitro activity of beta-lactam/beta-lactamase inhibitor combinations against gram negative bacteria.

BACKGROUND & OBJECTIVE: Currently, the use of beta-lactamase inhibitors in combination with beta-lactam antibiotics represents an effective measure to combat a specific resistance mechanism of beta-lactamase producing organisms. Knowledge about the susceptibility profile of bacteria to different combination agents available is essential to guide appropriate treatment of severe infections in hospitalized patients. The present study compares the in vitro activity of three commercially available beta-lactam/beta-lactamase inhibitor combinations (piperacillin/tazobactam, cefoperazone/sulbactam, ticarcillin/clavulanic acid) against beta-lactamase producing gram negative bacteria in a tertiary care hospital in north India. METHODS: A total of 9004 consecutively isolated extended spectrum beta-lactamase (ESBL) producing gram negative bacteria isolated from various clinical samples from patients admitted to the All India Institute of Medical Sciences, New Delhi, from September 2003 to August 2004 were included in the study. These isolates were screened for ESBL production by the inhibitor based test recommended by the National Committee for Clinical Laboratory Standards (NCCLS). Antibiotic susceptibility testing was carried out by disc diffusion method as per NCCLS guidelines. RESULTS: Of the 9004 isolates tested, 3232 (35.89%) were sensitive and 568 (6.31%) were resistant to all three combination agents, and rest 5204 (57.80%) were resistant to at least one of the combinations. Susceptibility to piperacillin/tazobactam, cefoperazone/sulbactam, and ticarcillin/clavulanic acid was 81.37, 76.06 and 45.48 per cent respectively. Piperacillin/tazobactam exhibited significantly (P<0.05) greater antimicrobial activity against Pseudomonas spp., Escherichia coli and Klebsiella spp. compared to cefoperazone/sulbactam. INTERPRETATION & CONCLUSION: Overall piperacillin/tazobactam was observed to be the best combination agent followed by cefoperazone/sulbactam in our setting. This difference in activities of these combination agents needs to be evaluated further by ascertaining their efficacy in clinical studies.

In vitro efficacy of ciprofloxacin and gentamicin against a biofilm of Pseudomonas aeruginosa and its free-living forms.

BACKGROUND: Infection with Pseudomonas aeruginosa is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). With chronicity of infection, the organism acquires a mucoid phenotype and grows as microcolonies in a biofilm in the respiratory passages of the host. This acts as a protective niche and helps the organism to evade the host immune response. In the biofilm the organism has a high resistance to antibiotics, leading to problems in eradication, and poses a therapeutic challenge. We studied the antimicrobial susceptibility of P. aeruginosa ATCC 27853 in a biofilm and as free-living forms against ciprofloxacin and gentamicin, the commonly used antibiotics in patients with CF. METHODS: Biofilm formation of P. aeruginosa ATCC 27853 was characterized by in vitro biofilm formation assay. The biofilm was detected by light microscopy and quantitated by measuring the absorbance at 575 nm and by viable bacterial counts. After the maximal biofilm was established, the effect of various concentrations of ciprofloxacin (1, 2 and 4 microg/ml) and gentamicin (4, 8, 16, 32 and 64 microg/ml) was observed and the minimal biofilm eradication concentration (MBEC) determined. The minimal bactericidal concentration (MBC) of both the antibiotics was determined against the free-living forms of the organism. The MBEC of the two antibiotics was further compared with the MBC. RESULTS: On microscopic examination, the maximal biofilm of P. aeruginosa was established on a coverslip at 12 hours, the maximum absorbance was at 575 nm and viable counts were observed at 12 hours, which corresponded to the maximal biofilm production. The organisms in the biofilm showed a 4-fold greater resistance against ciprofloxacin and gentamicin as compared to the free-living forms. CONCLUSION: In biofilm, P. aeruginosa shows greater resistance against antibiotics. This renders these antibiotics ineffective, leading to chronic and persistent infections.

Species prevalence and antimicrobial susceptibility of enterococci isolated in a tertiary care hospital of North India.

The present prospective study was carried out to determine the species distribution and antimicrobial susceptibilities of enterococci isolated from clinical samples in a tertiary care hospital of North India. Enterococcus species isolated from blood, urine, pus, sterile fluids and the hospital environment from October 2003 to January 2004 were identified by standard biochemical tests. Antimicrobial susceptibility testing was performed by the disk diffusion method as per NCCLS guidelines. Out of a total of 105 Enterococcus species recovered during the study period, E. faecium (42.90%) and E. faecalis (40.00%) constituted the predominant isolates. Enterococcus faecium was the commonest blood culture isolate while E. faecalis predominated pus and urine samples. Other species isolated were E. mundtii, E dispar, E. durans, E. avium, E. raffinosus and E. gallinarum. High-level aminoglycoside resistance was detected in 73.3% of isolates. Resistance to vancomycin, teicoplanin and linezolid was not detected. Prevalence of a wide variety of Enterococcus species in clinical samples together with their variable antimicrobial susceptibility patterns emphasizes the need for routinely carrying out detailed speciation and in vitro susceptibility testing of enterococcal isolates in the clinical bacteriology laboratory.

Enterococcal bacteraemia in a tertiary care hospital of North India.

A prospective study was conducted to determine clinical and bacteriologic features and antibiotic resistance pattern of enterococci isolated from cases of bacteraemia over a 7-month period. A total of 103 patients were identified during the study period whose blood culture was found to be positive for Enterococcus species. Bacteraemia was nosocomially acquired in 100 patients and community acquired in three. Enterococcus faecalis was isolated in 99 patients and E faecium in four. Bacteraemia was polymicrobial in 34 patients. Majority of patients had serious underlying diseases and were on prior therapy with cephalosporins. A source of bacteraemia was found in 59 patients (57.2%); intravascular catheters being the most common identifiable source. Overall mortality rate was 5.8%. High level aminoglycoside resistance was found in 76 (73.8%) of the enterococcal isolates. Vancomycin resistance was not found in any of the isolates. Bacteraemia due to enterococci is emerging as a significant clinical problem in hospital settings. A watchful vigilance is therefore required as regards their antibiotic resistance pattern particularly high level aminoglycoside resistance and vancomycin resistance. In addition hospital practices like prolonged use of in situ catheters and inadvertent antibiotic usage need to be minimised.

The study of bacterial flora of different types in hospital waste: evaluation of waste treatment at Aiims Hospital, New Delhi.

Bio-medical waste management rules were formulated in response to the worldwide public concern over medical waste. The practice of separation into different types of waste in health care institutes should be evaluated more scientifically. Due to a lack of data from the Indian sub-continent, this study was initiated at a tertiary care hospital. Samples were collected from different types of waste at the hospital, at different time intervals, for microbiological evaluation. The results reveal that the microbial flora isolated from infectious waste and general waste from the hospital are similar. The samples from general waste in this study reveal many types of pathogens. The bacteria present in the waste initially was low in quantity, but they replicated rapidly over time so that significant numbers were detected by 24 hours, due to environmental factors which were favorable for growth during this period. This study strongly suggests that waste should be removed from the hospital within 24 hours of its generation to prevent environmental contamination caused by any accidental spillage of waste. General waste generated in the hospital should be treated similar to infectious waste, as it can be equally hazardous.

Streptococcus pyogenes meningitis.

Group A Streptococcus (GAS) is a rare cause of meningitis. Although it has a high mortality, the condition is easily treatable if diagnosed early since the bacteria retains its sensitivity to many antimicrobials. The authors report here two cases of GAS meningitis along with a review of world literature.