Virulence factor profiles, phylogenetic background, and antimicrobial resistance pattern of lactose fermenting and nonlactose fermenting Escherichia coli from extraintestinal sources.

Context: In recent years, nonlactose fermenting (NLF) Escherichia coli have been increasingly isolated in the microbiology laboratory, but their clinical significance has not yet been clearly elucidated. Aims: To characterize the lactose fermenting (LF) and NLF isolates on the basis of their virulence factors, phylogenetic background, and drug resistance property. Settings and Design: This descriptive study was carried out in a multi‑specialty tertiary care hospital. Subjects and Methods: Three hundred nonrepeat E. coli isolates from inpatients were studied. Isolates were differentiated as LF and NLF on the basis of colony characteristics on MacConkey’s agar. Possession of virulence and drug resistance genes was determined by multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Antibiotic sensitivity testing was performed by disk diffusion method. Results: Of 300 isolates 39 (13%) were NLF isolates. Maximum number of NLF isolates belonged to phylogroups B2 and D when compared with LF isolates. The incidence of iutA, hlyA, and neuC genes were significantly higher in NLF isolates. The presence of drug resistance genes such as AmpC gene, SHV, and CTXM were higher in LF isolates. Conclusions: LF isolates demonstrated a higher antimicrobial resistance and NLF isolates possessed higher virulence properties. The microbiology laboratory should report lactose fermentation profile as it may help the physician to initiate appropriate treatment.

Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for rapid diagnosis of neonatal sepsis.

Background & objectives: The difficulties in diagnosis of neonatal sepsis are due to varied clinical presentation, low sensitivity of blood culture which is considered the gold standard and empirical antibiotic usage affecting the outcome of results. Though polymerase chain reaction (PCR) based detection of bacterial 16S rRNA gene has been reported earlier, this does not provide identification of the causative agent. In this study, we used restriction fragment length polymorphism (RFLP) of amplified 16S rRNA gene to identify the organisms involved in neonatal sepsis and compared the findings with blood culture. Methods: Blood samples from 97 neonates were evaluated for diagnosis of neonatal sepsis using BacT/Alert (automated blood culture) and PCR-RFLP. Results: Bacterial DNA was detected by 16S rRNA gene PCR in 55 cases, while BacT/Alert culture was positive in 34 cases. Staphylococcus aureus was the most common organism detected with both methods. Klebsiella spp. was isolated from four samples by culture but was detected by PCR-RFLP in five cases while Acinetobacter spp. was isolated from one case but detected in eight cases by PCR-RFLP. The sensitivity of PCR was found to be 82.3 per cent with a negative predictive value of 85.7 per cent. Eighty of the 97 neonates had prior exposure to antibiotics. Interpretation & conclusions: The results of our study demonstrate that PCR-RFLP having a rapid turnaround time may be useful for the early diagnosis of culture negative neonatal sepsis.

Asymptomatic Bacteriuria with Escherichia coli in Type 2 Diabetic Patients: An Unresolved Riddle.

Asymptomatic bacteriuria (ASB) is a common finding, but there is a considerable controversy about the appropriate management of bacteriuria. ASB was found to be three times higher in patients with diabetes, especially in women when compared to non-diabetic counterpart. Asymptomatic bacteriuria is the presence of bacteria in the urine presenting without any clinical symptoms of UTI. The objective of this review is to highlight the studies done on ASB in diabetes patients with special reference to Escherichia coli (E. coli), risk factors and its management. The review showed that increasing age, females, post-menopausal status, poor glycaemic control, long duration of diabetes, microalbuminuria, leukocyturia ,poor hygiene were associated with ASB. Available literature does not support the use of antibiotics, however short term trials have shown benefit with topical esteriol. Further clinical trials are needed.

Molecular characterization and clinical significance of New Delhi metallo-beta-lactamases-1 producing Escherichia coli recovered from a South Indian tertiary care hospital.

Context: The increased rate of infection by New Delhi metallo-beta-lactamases-1 (NDM1) producing Escherichia coli is a major concern since they show a high rate of drug resistance and are responsible for mortality and morbidity. Aims: To characterize the NDM1 producing E. coli isolates and their impact on patients’ clinical outcome. Settings and Design: This descriptive study was carried out in a multi-specialty tertiary care hospital. Materials and Methods: Three hundred nonrepeat strains of E. coli from inpatients were included in the study. Modifi ed Hodge test and metallo-beta-lactamases (MBL) e-test were performed to detect carbapenemase and MBL activity. Polymerase chain reaction (PCR) technique was performed to detect NDM1. NDM1 positive isolates were further tested for plasmid mediated AmpC, blaCTX, blaSHV, blaTEM genes and also for phylogrouping by PCR methods. Treatment and patients’ clinical outcome were also analyzed. Results: Out of 300 isolates, 21 (7%) were MBL producers by phenotypic methods. Of this, 17 (81%) were NDM1 positives, among the NDM1 producers 6 (35%) isolates were belongs to phylogroups D followed by A 5 (29%), B1 4 (24%) and B2 2 (12%), 15 (88%) isolates were blaCTX-M positive suggestive of extended-spectrum beta lactamase producing strain and 7 (47%) were positive with CIT type of AmpC. With the follow-up of the patients, it was found that 12 (71%) recovered and 3 (18%) developed relapses, and mortality was seen in 2 (12%) patients. Conclusions: NDM1 producing isolates showed a high degree of drug resistance but can be treated with suitable antimicrobials, in the majority. Early detection and choice of appropriate antibiotics may help in reducing mortality and morbidity.

Genomic analysis and clinical importance of Escherichia coli isolate from patients with sepsis.

Context: Escherichia coli is a major cause of bloodstream infections and death due to sepsis. Bacteremic isolates harbor a signifi cantly greater repertoire of virulence factors (VFs) in contrast with commensal E. coli isolates. Aims: The aim was to determine the relationships between E. coli VFs, phylogenetic groups, and their clinical importance. Settings and Design: This descriptive study was carried out in a multi-specialty tertiary care hospital. Materials and Methods: Escherichia coli isolates from consecutive episodes of bacteremia in 100 patients were screened for their VFs, phylogenetic group, and their effect on patient’s clinical outcome. Virulence genes of all isolates were determined by multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Estimation of risk of death was calculated using APACHE score II calculator. Results: Of the 100 patients, the most common predisposing factors were diabetes (42%), followed by carcinoma (23%). On analysis of the VF genes of the isolates, a majority of strains (88%) were possessing the fi mH gene followed by iutA (76%), papC (44%), cnf1 (16%), hlyA (16%) and neuC (5%) respectively. Phylogenetic analysis revealed that 25 (25%) isolates belonged to phylogroup A, 8(8%) strains to group B1, 30 (30%) were from group B2 and 37 (37%) were from group D. The incidence of iutA gene was signifi cant in higher APACHE II score group. Conclusions: Our fi ndings indicate that virulent as well as commensal strains are capable of causing sepsis. Host related predisposing factors, adherence factors, and iron uptake are essential for the survival of the sepsis inducing strains.

Clinico-microbiological study of infections in the intensive care unit and study of antimicrobial resistance in bacterial isolates.

Infectious disease specialists have long recognized that the risk of ICU patients acquiring nosocomial infections is 5-10 times greater than those in general wards. Several factors such as severe underlying disease, multiple illnesses, malnutrition, extremes of age, immunosuppression, use of invasive medical devices, ICU crowding and animate reservoirs increase the risk of acquiring infections in the ICU. Out of 113 isolates obtained in our study, 32.7% were from ventilator-associated pneumonia patients and 17.7% from urinary tract infection patients. The major isolates were Staphylococcus aureus (21.2%) and Klebsiella spp. (20.4%). Methicillin resistant Staphylococcus aureus (MRSA) and ESBL producing Klebsiella and E. coli were the major drug resistant bacteria isolated and associated with significant mortality. Control of these infections poses a major problem in treating the patients because of the rising trend of drug resistance among these bacteria.

Characterization of plasmid mediated AmpC producing Escherichia coli clinical isolates from a tertiary care hospital in South India.

Context: Plasmid mediated AmpC (pAmpC) β-lactamase producing Escherichia coli are an emerging problem worldwide as they are now exhibiting resistance to multiple classes of antibiotics and are a major cause of therapeutic failure. Aims: The aim of this study was to characterize pAmpC β-lactamase producing extraintestinal E. coli, their phylogenetic distribution, resistance pattern, treatment options, and impact on patient’s clinical outcome. Settings and Design: This descriptive study was carried out in a multi-specialty tertiary care hospital. Materials and Methods: A total of 300 clinically signifi cant, non-repeat isolates were studied. AmpC disk test was used for phenotypic AmpC-β- lactamase detection. Molecular types of pAmpC were determined by a multiplex polymerase chain reaction (PCR). Phylogenetic analysis was performed by triplex PCR methods. Metallo-beta-lactamase (MBL) detection was done by E test. Antibiogram, treatment, and clinical outcome were collected in a structured proforma. Results: Although 95 isolates (32%) were phenotypically positive for AmpC, PCR detected CIT type of AmpC gene in only 37 isolates. Majority of strains were from phylogroup A (85%) and B1 (58%) which are considered as commensal groups. Co-production of ESBL’s was observed in 33 strains and 5 strains were found to be MBL producers. Most widely prescribed antibiotics were 3rd generation cephalosporins (30%), carbapenems (19%) and aminoglycosides (16%). Conclusions: Plasmid mediated AmpC producing isolates were found to exhibit a high degree of drug resistance, and they mainly belonged to commensal strains possibly due to misuse of antibiotics. Proper antibiotic policy is required to limit the spread of pAmpC producers or else it will lead to a therapeutic dead end in the near future.

Nosocomial infections in neonatal intensive care units: Profile, risk factor assessment and antibiogram.

Objective. To determine the profile and risk factors of neonatal nosocomial infections and determine the antibiotic susceptibilities of these isolates. Methods. Cohort study was conducted at Kasturba Medical College, Mangalore, from July 2005 to September 2006. Neonates admitted for more than forty-eight hours in the NICU, who developed infections/ sepsis as evidenced by the clinical findings were included in the study. Chi-square test, Proportion tests were used, P value of <0.05 was considered significant. Results. Extended spectrum beta lactamase (ESBL) producing Klebsiella species and Methicillin resistant Staphylococcus aureus (MRSA) were the predominant nosocomial pathogens. Significant risk factors included prematurity, low birth weight and increased duration of hospital stay. Conclusion. A revised infection control program with emphasis on handwashing techniques and antibiotic cycling helped to control these hospital infections.

Urinary tract infection due to Enterobacter sakazakii.

Enterobacter sakazakii is a rare but important cause of necrotizing enterocolitis, bloodstream infection and central nervous system infections in humans, with mortality rates of 40-80%. It has not been reported to cause urinary tract infection. We report a case of urinary tract infection due to E. sakazakii in a 63-year-old lady with chronic renal failure.

An outbreak of extended spectrum beta-lactamase producing Klebsiella pneumoniae in a neonatal intensive care unit.

Klebsiella pneumoniae has long been a prominent cause of nosocomial infections and outbreaks have been observed in the intensive care units and in high risk groups. We present here a brief report on an outbreak of Klebsiella pneumoniae which occurred in a neonatal intensive care unit in our teaching hospital. As neonates are at highest risk for acquisition of Klebsiella pneumoniae producing extended spectrum beta-lactamase, infection control policies and procedures should be strictly followed to prevent such outbreaks.

Role of multiple induced sputum examination in the diagnosis of Pneumocystis carinii pneumonia.

We evaluated the usefulness of repeated nebulized saline induced sputum examinations among 60 HIV infected patients clinically suspected to have Pneumocystis carinii pneumonia (PCP). We found that the first sample was positive for 15 episodes (21.4%); the second sample was positive in 33 episodes (47.1%); the third sample was positive in 22 episodes (31.4%). Repeated nebulized saline induced sputum examination imporved the yield of Pneumocystis carinii and enhanced the sensitivity of a positive result. This technique is simple, cost-effective, non-invasive, and reliable. We recommend the examination of multiple induced samples of nebulized saline induced sputum in all HIV infected patients with suspected PCP. This recommendation may decrease the need for invasive procedures.

Chromobacterium violaceum septicemia.

Chromobacterium violaceum is an extremely rare human pathogen. We report a rare case of septicemia with multiple abscesses and otitis media in a newborn caused by chromobacterium violaceum.