Efficacy of levofloxacin loaded non-ionic surfactant vesicles (niosomes) in a Pseudomonas aeruginosa infection model in Sprague Dawley rats

Objective: To determine the efficacy of levofloxacin loaded niosomes in treating Sprague Dawley rats infected with Pseudomonas aeruginosa (ATCC 27853). Design and Methodology: Three groups of six (6) animals were infected with a known dose of the pathogen i.e. Pseudomonas aeruginosa via the intraperitoneal (ip) route. At six (6) hours post infection the infected animals were treated with drug free niosomes (control), free levofloxacin (conventional) and levofloxacin trapped in niosomes (ip). Blood was collected via tail snips at days 0,1,3,5,7 and 10 for complete blood counts and viable bacterial counts by colony forming units (CFU/µl). At day 10 the animals were sacrificed and samples from the kidney, liver and spleen were examined for bacterial counts. Results: All animals in the control group succumbed to the infection; one animal from the conventional group died. All niosome treated animals survived. The mean lymphocyte count (X109) was lower for the niosome (7.258±1.773) versus conventional (17.684±10.008) (p<0.03) treated groups at day ten (10). Neutrophil counts (X109) were lower for the niosome (2.563±1.609) versus conventional (6.2±6.548) p<0.02) treated groups. The CFUs in the bloodstream were similar for both treatment groups; the niosome treated group showed greater reduction in liver, kidney and spleen CFUs versus the conventional group (1.33±2.074) vs (5.8± 3.74) (p< 0.043), (1.5±2.35) vs (9.6±8.65) (p< 0.038) and (3.8 4.71) vs (25.6 14.66) (p<0.007) respectively. Conclusions: Further work is recommended on niosomes as a drug delivery system to treat intracellular infections.

Antimicrobial susceptibility of clinical isolates of Pseudomonas aeruginosa from dogs in Grenada

A total of 44 isolates of Pseudomonas aeruginosa were recovered from various clinical conditions during the last 5 years from dogs in Grenada. The majority of isolates originated from otitis, and skin conditions including dermatitis, wounds, and abscesses. The isolates were tested for their susceptibility to 6 antibiotics using a standard disk diffusion test. Resistance was least to gentamicin (9.8%), followed by enrofloxacin (15.8%), and neomycin (41.8%). Resistance to tetracycline was 85.3%, and all isolates showed inherent resistance to amoxicillin-clavulanic acid and cephalothin.

Emergence of KPC-producing Pseudomonas aeruginosa in Trinidad and Tobago.

In 2006, the first isolate of KPC-2-producing Pseudomonas aeruginosa in the world was identified in Colombia. Recently, similar strains have been reported in Puerto Rico. We now report KPC-2-producing P. aeruginosa in Trinidad and Tobago. Surveillance for similar strains is warranted, considering their wide geographic spread and known association with mobile genetic elements.

Antimicrobial susceptibility survey of Pseudomonas aeruginosa strains isolated from clinical sources

A two-year prospective study of 554 Pseudomonas aeruginosa isolates was recovered from various clinical sources throughout Trinidad, and their resistance patterns to antipseudomonal antimicrobial agents were determined. Of the 554 P. aeruginosa isolates, 20.6% (114/554) were community isolates, 17.3% (96/554) from the intensive care unit (ICU), 10.1% (56/554) from the nursery, and the remaining 52% (288/554) were from other hospital inpatient services. Respiratory tract infections were the predominant source of P. aeruginosa isolates from the ICU--46.9% (45/96)--and nursery--21.4% (12/56), whereas wounds were the principal source of P. aeruginosa from the surgical services--77.0% (141/183). Community isolates of P. aeruginosa were predominantly from ear--100% (51/51)--and urinary tract infections--35.5%, (33/93). The overall prevalence of resistance was low for both hospital isolates (13.9%) and community isolates (3.8%). All community isolates were fully sensitive to four of the nine antimicrobials tested. Resistance rates among community strains ranged from 2.6% (ciprofloxacin and ceftazidime) to 12.3% for piperacillin. All isolates from hospital were fully sensitive to imipenem, but resistance rates for the other drugs ranged between 2.5% and 27.3%. The study showed that the overall resistance pattern of P. aeruginosa was relatively low. This is an encouraging observation but invites caution since resistance to the newly introduced drug, cefepime, has now emerged within the hospital environment and may present serious therapeutic problems within the near future. Policies governing the use of antimicrobials in many institutions are lacking. Such policies must be instituted in order to limit the spread of resistance and also to reduce the emergence of resistance to newly commissioned drugs within the country.

Nosocomial infection in an Intensive Care Unit in a private hospital

The nosocomial infection rate in an Intensive care unit (ICU) of a private hospital was assessed during an 18-month survey. From 629 admissions to the ICU, 139 hospital-acquired infections were identified. The rate was 22.1 percent compared to the overall nosocomial infection rate of 15.3 percent for the entire hospital. In the ICU, the main infections occurred in the respiratory tract, 41 (29.5 percent), followed by surgical wounds, 35 (25.2 percent), urinary tract, 28 (20.1 percent) and the blood stream, 24 (17.3 percent). From 165 bacterial isolates, 80 percent of isolates were gram-negative rods, with P aeruginosa, 48 (36.6 percent), being the predominant gram-negative isolate followed by Klebsiella pneumoniae, 27 (20.6 percent), and Enterobacter sp, 22 (16.8 percent). The main gram-positive isolates were S aureus, 23 (41.8 percent), coagulase-negative Staphylococci, 17 (30.9 percent), and Enterococci, 11 (20.0 percent). Of the 23 S aureus strains, 15 (65.2 percent) were methicillin-resistant (MRSA), (8 MRSA were from surgical wounds, 5 from the respiratory tract and 2 from infected urine). Only 2 of the 17 (11.8 percent) coagulase-negative staphylococci were methicillin-resistant, and both were isolated from wounds. Resistance to ampicillin and augmentin (amoxicillin-clavulanic acid) was high, 81.9 percent and 55.4 percent, respectively. Gentamicin, azteronam, piperacillin-tazobactam showed resistance rates of less than 15 percent. Infection control measures aimed at reducing nosocomial infections at the hospital are often frustrated by apathy of hospital administrators who apparently are insensitive to the high nosocomial infection rate. Effort by the infection control team through seminars, lectures and newsletters have begun to show improvements in attitude and awareness of staff to infection control and preventative measures within the institution. (AU)

Frequency of occurence and antimicrobial resistance in isolates of bacterial conjunctivitis in patients at the University Hospital of the West Indies [abstract]

OBJECTIVE: There is paucity of published data on bacterial conjunctivitis in patients at the University Hospital of the West Indies and the wider community in Jamaica. This report analyses 208 bacterial isolates from 198 eye swab cultures of patients with clinical diagnosis of conjunctivitis in this hospital. METHODS: Culture of eye swabs was done by routine methodology, and anti-microbial susceptibility tests were performed by the standard disc-diffusion technique. RESULTS: Two hundred and eight bacterial isolates were encountered in the 198 ocular cultures. Eighty of these (32.9 percent) were likely contaminants (normal commensal from skin of the eyelid). The common isolates in order of frequency in the remaining 128 were: Haemophilus influenzae pneumoniae 12 (9.4 percent) and Pseudomonas aeruginosa 5 (3.9 percent). These four organisms together accounted for over two-thirds (69.5 percent) of the 128 isolates. More than 90 percent of these strains were susceptible to chloraphenicol and gentamicin. CONCLUSIONS: The contamination rate in eye swab cultures is very high and there is need for improvement of the collection procedures. Haemophilus influenzae remains the most common pathogen of bacterial conjunctivitis as in many other parts of the world. The common eye preparations such as chloramphenicol and gentamicin (alternatively, tobramycin) continue to be highly effective against pathogens from conjunctivitis at the University Hospital of the West Indies. (AU)

Surveillance of nosocomial "alert organisms" at the UHWI - 1995-1997 - Poster presentation

This survey was conducted to determine the types, prevalence and distribution of "alert" organisms within the UHWI. Continuous surveillance of "alert organisms" at the University Hospital has been conducted since 1995. Amongst the Gram positive isolates, Methicillin-resistant Coagulase-negative Staphylococci and Enterococci were more often reported (30 - 37 percent) than Methicillin-resistant Staph. aureus (9 - 13 percent) (MRSA). Pseudomonas aeruginosa accounted for the largest number of Gram-negative isolates (25 - 36 percent) followed by Acinetobacter and Klebsiellae (11 - 19 percent). Resistance to several groups of antibiotics was especially notable in Acinetobacter and Klebsiellae during 1997. Extended-spectrum betalactamase-producing Klebsiellae emerged in late 1996 (6.3 percent) and showed an increase in 1997 (37.1 percent). Ceftazidime-resistant Ps. Aeruginosa increased from 2.7 percent to 7.2 percent over the period. The types of organisms and their characteristic antibiogram can be used to direct further treatment and infection control policies.(AU)

Cancrum oris (noma) in a patient with acute lymphoblastic leukaemia. A complication of chemotherapy induced neutropenia

Cancrum oris (noma) has been most commonly described in malnourished debilitated children with poor oral hygiene following systemic childhood infections such as measles, pertussis or scarlet fever. We describe a patient who developed this condition during a period of profound neutropenia following cytotoxic chemotherapy for acute lymphoblastic leukaemia(AU)

Nosocomial infection in a neonatal unit - abstract

This study of nosocomial infection (NI) was conducted to obtain baseline data on NI between epidemics. All infants who were admitted to the Special Care Unit, Queen Elizabeth Hospital, and who stayed there for > 48 hours in the period June 1 to October 31, 1989, were enrolled in the study. NI was defined as an infection which was not present at birth or incubating in the mother and beginning 48 hours after birth, and was classified as major (meningitis and bacteraemia) and minor (all other infections). There were 28 NIs in 22 neonates with a mean age of 4.5 days, gestational ages ranged from 31 to 40 weeks, and birth weight from 1 to 5 kg. Conjunctivitis (50 per cent) and bacteraemia/meningitis (23 per cent), were the commonest NIs. Psuedomonas aeruginosa (21 per cent) was the commonest organism cultured. Four of six major NIs were due to gram-negative and the rest to gram-positive organisms. The NI rate was 10 per 100 discharges and no deaths from NI occurred. It is concluded that there is a high level of NI, mainly gram-negative organisms, in the neonatal unit, and a strong case exists for a larger improved unit, continuous surveillance and continuing education on prevention of NI (AU)

In vitro activity of ceftazidime and other antipseudomonal antibiotics against mucoid strains of pseudomonas aeruginosa

The minimum inhibitory concentration of ceftazidime, was determined for 132 mucoid strains of pseudomonas aeruginosa (MPA) isolated from patients with cystic fibrosis (CF), using an agar tube dilution method. Using strains collected over a ten-year period, we found that 98 percent were susceptible to achievable serum concentrations with MIC50 and MIC90 of 1.2 and 3.1 ug/ml, respectively. Susceptibility of 60 of these strains was also determined for cefoperazone (100 percent susceptible), tobramycin (97 percent), and carbenicillin (83 percent). Susceptibility of stored strains was similar to that of fresh isolates. We have shown that strains of MPA in a U.S. population were more susceptible to ceftazidime than those currently reported from Europe where this antibiotic was introduced earlier. Cefoperazone, another third generation cephalosporin which has received less attention in the treatment of patients with CF, is as active as ceftazidime in vitro. These data provide a basis for determining the future impact of these agents on pseudomonas susceptibility (AU)

Bacteriology of sickle cell leg ulcers

The bacteria isolated on aerobic and anaerobic culture were compared in 80 unilateral ulcers in patients with homozygous sickle cell (SS) disease, 62 superficial skin lesions and in 30 diabetic ulcers. In SS disaese the bacterial flora was predominantly aerobic and polymicrobial with Staphylococcus aureus, Psuedomonas aeruginosa and beta haemolytic streptococci being the major isolates. Repeat sampling of 26 ulcers over a period of 23 weeks indicated the persistence of these organisms, either singly or in combination in 21 ulcers.Although a variety of Enterobacteriaceae were recovered no single genus predominated and these organisms did not normally persist on follow up. Simultaneous swabs from bilateral ulcers revealed similar if not identical flora in most cases, indicating good predictive value of a single swab in patients with multiple ulcers. Corynebacterium diphtheriae was recovered from 8 ulcers and 4 of these strains were toxigenic. By contrast the superficial skin lesions grew mainly S. aureus and beta haemolytic streptococci, and the diabetic ulcers yielded a mixed growth of streptococci, Enterobacteriaceae and anaerobes. The recovery of known skin pathogens from most sickle cell leg ulcers, the persistence of these organisms, and the presence of associated lymphadenopathy, indicates that infection may be a significant factor in the pathology of these lesions

Insignificance of colonic bacteria in the sputum of patients in a new ICU

Over a 12-month period, 27 percent of patients in a new ICU grew bacterial pathogens from sputum or tracheal cultures. The commonest isolates were Pseudomonas aeruginosa and Klebsiella species. Endotracheal intubation, the length of time intubated, and antimicrobial therapy all predisposed to the isolation of organisms from sputum. No patient developed a gram-negative pneumonia, and there was no case of septicemia associated with a positive sputum culture. The presence of epithelial or pus cells in sputum was unrelated to the culture results. It was concluded that the growth of colonic bacteria from sputum or tracheal aspirates was of little prognostic or clinical significance. No significant common environmental site or cross-infection pathway was identified: sinks were contaminated by patients rather than vice versa. Most sputum isolates were probably endogenous in origin. (AU)

Typing of pseudomonas aeruginosa by production of pyocines

Pyocine typing of 310 isolates of Psuedomonas aeruginosa was carried out using 15 indicator strains. Type 1 was found to be the commonest type recovered from clinical environmental sources, the other main pyocine types being types 10, 6, 19, and VA 39. Further differentiation of isolates led to the identification of sub-types a, b, c, d, and f, of which sub-type a was the most frequent. Two additional indicator strains, IA and IB were found to be of limited value in further delineation of a qualitative nature of pyocines produced by the isolates. The relative constancy of pyocine types obtained in replicate isolates on different occasions from the same site in the same patient suggested the stability of pyocine production in vivo and reproducibility of the method in vitro. The usefulness of pyocine typing in epidemiological investigations is indicated by the detection of some cases of cross-infection due to rare pyocine types in the University Hospital during the period of this study (AU)

Effect of pseudomonas aeruginosa and staphylococcus pyogenes on the rate of wound healing in mice

The effects of Pseudomonas aeruginosa and Staphylococcus pyogenes and sterile dirt on the rate of wound healing in Albino Swiss mice have been studied. Framycetin sulphate, Alfamel, cod liver oil and honey were used to treat all three groups. The rate of healing was unaffected by treatment, but was significantly dependent on the infecting organism (AU)

Preliminary survey of sensitivity of local strains of pseudomonas pyocyanea to carbenicillin

Fifty (50) strains of 'Ps. pyocyanae' isolated in Jamaica were tested for sensitivity to carbenicillin. The M.I.C. of carbenicillin for twenty (20) of these strains show that most are inhibited IN VITRO by 25-50 æg/ml. (AU)