Research Article - (2015) Volume 6, Issue 2

Nosocomial Infections Incidence Rates, Bulgaria, 1999-2011

Todorova-Christova M1*, Vatcheva R2, Filipova R3, Kamenova T3, Arnaudov Y4, Radulova Y4, Ivanov I1 and Dobreva E1
1National Center of Infectious and Parasitic Diseases, Sofia, Bulgaria
2University Hospital “Queen Yoanna”, Sofia, Bulgaria
3Ministry of Health, Sofia, Bulgaria
4National Center of Public Health and Analyses, Sofia, Bulgaria
*Corresponding Author: Todorova-Christova M, National Center of Public Health and Analyses, Sofia, Bulgaria, Tel: +359 2 94 46 99 Email:

Abstract

The study presents an analysis in two parts of the officially registered NI in the country by the computerized information system (CIS-NI) in the course of a 13-year period (1999-2011). The system employs two types of indicesincidence rate (morbidity, recalculatred in the study per 1000 patients discharged) and percentage distribution (frequency distribution, relative frequency distribution) by infection sites and microbial agents. This part discusses the overall NI incidence rates by hospital and wards categories, accentuating upon pediatric and intensive care wards-anesthesiology and resuscitation, intensive therapy.

The average incidence rate is 10% at the following distribution by infection sites: VAP-5%, surgical site infections (SSI) and pulmonary infections (the latter including bronchitis, bronchiolitis, pneumonia, non-associated with procedure of endotracheal intubation) of 16-18% each; urinary tract infections (UTI) 13-15%; sepsis 4-5%, enteric, skin infections, of the sense organs, intraabdominal and cardiovascular system infections-approximately 2% of each group, endometritis and other gynecologic infections-1%, mastitis in young mothers-0.1%. Microbiologically diagnosed are 50-60% ?f the infections as a total and in 40-50% unconfirmed and unexamined microbiologically.

E. coli and S. aureus are identified in about one third of the total number of infections, the rest isolates pertain to opportunistic bacterial species, known for their multiresistence: Klebsiella spp, Pseudomonas spp, Acinetobacter spp etc.

The incidence rate of infections ranges within low limits, e.g, LRTIs (pulmonary infections)-pediatric wards-upto 3%; VAP/ pulmonary infections-resuscitation (A&R) 15-19%, intensive therapy (IT) 5-8%; UTIs-resuscitation, urology-13%; SSIs-burn units-38%, septic surgery-23%, vascular surgery-11%; sepsis-burn units-22%, resuscitation-8%, cardiovascular surgery-6%, ICUs-5%.

The official registration system provides reliable information on a national level for the purpose of NI surveillance and control. The system interpretes the original data of the wards in basic indices as incidence and microbial isolates‘ distribution. This official database reflects the efforts in the sphere of NI prevention and control. Possible additional links to the system would contribute to direct comparisons of indices regarding the care for patients undergoing risk procedures.

Keywords: Nosocomial infections; Computerized information system-nosocomial infections; Ventilator-associated pneumonia; Acute upper respiratory tract infections; Lower respiratory tract infections [(LRTIs), pulmonary infections)]; Surgical site infections; Urinary tract infections; Sepsis; Anesthesiology, resuscitation and intensive care units; Anesthesiology and resuscitation; Intensive care units; Intensive therapy

Introduction

Nosocomial infections (NI) surveillance and control is estimated as an important task of the healthcare organization in our country. A national NI surveillance system was introduced in 1981, based on computer processing of the original documents from practically all health-care facilities. A reviewal of the indices adopted is made by means of official reports and specialized studies. However, distinct effects on the NI incidence are difficult to demonstrate, in spite of achivements made in the infection control in the country as effective education and training on the problems, an organization for control measures, reconstruction and modern technology equipment ensured for sterile services departments (SSDs) and hospital wards. The problems of nosocomial infections are related to a great extent to the adequacy of funds invested in infection control directly for the SSDs to be constructed and equipped according to the most exigible and strict regulatory requirements, the disinfection and sterilization acrtivities and the healthcare facilities construction/reconstruction and equipment to be subject to strict regulatory measures as well, the antibiotics policy to be conformable with the reference guides and the monitoring of the local hospital strains antibacterial resistance.

Objective

The present study analizes the nosocomial infections distribution in the country by infection sites and microbial isolates for the period 1999- 2011 on the basis of the official registration data of the computerized information system-nosocomial infections (CIS-NI). Two additional files, related to the observation of patients with risk procedures, and adapted with certain modifications from external sources, are proposed to be processed within the feed-back of the official system with the wards. The files are considered to be of use for the documentation of the personnel responsibilities in the care for patients on mechanical ventillation, and/or central/peripheral line.

Materials and Methods

In this first part of the study the analysis of nosocomial infections distribution in the country is based on the indices submitted by CISNI, i.e. distribution by major NI classificatoion groups and wards. A comparatively long period-from 1999 to 2011 including, has been followed up with certain highlights of 2010-2011 data.

CIS-NI operates with incidence rate indices, an analogue of the term “morbidity rate”, calculated in the case of NI as a proportion of the number of infections (in a numerator) to the patients discharged (in a denominator), multiplied by 100. However, in view of the comparability with some internationally adopted criteria for estimation of NI distribution, CIS-NI values have been recalculated in our study per 1000 patients discharged.

The study demonstrates:

• NI overall incidence rates by infection sites;

• NI overall percentage distribution by infection sites and microbial isolates.

Rates and percentages are presented in details regarding two subcategories of wards:

• Pediatric wards;

• Intensive care wards-anesthesiology and resuscitation, intensive therapy (intensive care units) and surgical wards.

The recent updates (2011) in CIS-NI have been taken into account, i.e.

• Updated nomenclature of the healthcare facilities in conformity with the agreements with the National Health Insurance Fund, surgical specialities better differentiated;

• Two corrections in the infections nomenclature of the original official document, i.e. first, requirement for the registration of the ventilator-associated pneumonia (VAP), and second, requirement of no longer reporting of the acute upper respiratory tract infetions (AURTIs) as a separate nosological (classification) group, the infections of this type included into the combined group of the “other infections”.

Results

Overall NI incidence rates by hospital catgory, overall percentage distrubution by infection sites and etiologic agents

Overall NI incidence rates: Recently, and for the last 3 years of the period studied concretely, NI reporting and registration have been maintained about 10%: 2009-10.2%; 2010-10.4%; 2011-9.4% (Table 1). The update of 2011 revealed similar registration level in the multi-profile hospitals for active treatment (MPHAT) corresponding to the former university and municipal hospitals (about 9%), and the specialized hospitals for active treatment (SHAT) corresponding to the former specialized hospitals-obstetrics and gynecology etc. (about 8%). A rate of about 30% is documented for psychiatric hospitals, a very low level of registration in the private healthcare facilities, the specialized centers (oncologic/psychiatric/dematology and venerology) and hospitals to other administrations about 3-4%. In the centers for medical and social care for children [(CMSCC)-orphanages-children up to 3 years of age], the markedly higher incidence values through the years, of more than 400% in 2011, have been determined mainly by the AURTIs reported (Table 1).

Hospital category 2011
MPHAT 8.9
SHAT 7.4
Other specialized 0.7
Private healthcare facilities 2.6
Psychiatric 28.2
(Onco-/psych-/dermatology and venerology) 3.8
Hospitals to other administrations 3.8
Other 1.1
CMSCC 476.1
All healthcare facilities 9.4
*The complete set of tables with the numerical data by years for the 1999-2011period is available with the editors.

Таble 1: NI overall incidence rates (per 1000 patients discharged) by hospital category for the period 1999-2011*.

Overall NI percentage distribution by infection sites (by infections classification groups)

The introduction of VAP as a separate nosological category (classification group) was imposed by the necessity of compliance with the admitted and demonstrated by all nosocomial infections studies substantial risk for the critically ill patients on mechanical ventillation, e.g.,

• Confirmed highest incidence rate of this complication in critically ill patients in resuscitation wards and intensive care units [1,2];

• Two fold higher mortality rate in patients with VAP in comparison with the intubated patients without such clinical data-(according to a review of the English and American references for the period 1990-2005) [3] and

• Additional costs due to the prolonged hospital stay [1,3].

As of 2011 the notified VAP cases in the country amount to 5% of all registered nosocomial infections (Figure 1): The proportion of the remaining infections groups corresponds to the data for the previous years, i.e. surgical site infections (SSIs) 16-18% for 2010- 2011; lower respiratory tract infections [(LRTIs) pulmonary infections (bronchitis, bronchiolitis, pneumonia, non-associated with a procedure of mechanical ventilation)] 18-17%; urinary tract infections (UTIs) 13- 15%; sepsis-about 4-5%, enteric, skin infections, of the sense organs, intraabdominal and of the cardiovascular system-about 2% respectively for each group, endometritis and other gynecological infections-about 1% as a total, mastitis in young mothers-0.1%. In 2011 the percentage of the “other” infections, not classified in the indicated groups, has increased from 5% to 24% on account of the AURTIs, already included into this group (Figure 1).

bacteriology-parasitology-Distribution-Nosocomial

Figure 1: Distribution of Nosocomial Infections by infection sites-Bulgaria, 2011.

Overall NI percentage distribution by etiologic agents

In the course of the period studied (1999-2011) CIS-NI data indicate that only in 50-60% NI are etiologically clarified, the rest 40- 50% as a total are microbiologically unconfirmed and untested. For the last two years (2010-2011) the percentage of the microbiologically unproven infections has increased from 17 to 27%, the unexamined microbiologically having been 22-23%. The infections, remaining without an etiological diagnosis are predominantly AURTIs. However, according to 2011 data, a part of important and of serious consequences infections like VAP, LRTIs (pulmonary) infections, SSIs, cardiovascular infections, UTIs, sepsis, have not been confirmed bacteriologically or are unexamined. The cardiovascular infections in approximately 60% ?f the cases have not been tested, and in another 24% no causative agent has been identified, presumably it refers to superficial phlebites in blood manipulations, usually treated conservatively, no necessity of sampling for testing (Tables 2 and 3).

Hospital category 1999 2000 2001 2002 2003 2004 2005 2006
University 35.93 35.45 40.44 35.66 37.81 37.15 38.87 37.97
First-rate municipal 39.28 39.16 36.92 41.60 42.45 43.99 43.38 42.63
Urban 43.18 41.26 40.70 42.10 41.80 40.54 39.94 36.64
Municipal 41.74 41.01 40.70 39.93 41.18 40.73 43.03 42.51
Specialized obstertrics and gynecology 18.53 13.96 14.80 14.83 12.59 16.02 17.07 20.48
Specialized pediatric 80.61 14.84 45.27 70.05 83.14 56.60 88.43 74.86
Other specialized 32.54 30.69 28.36 29.05 30.51 27.25 32.56 29.40
CMSCC 57.12 64.80 55.18 57.91 50.10 49.23 36.40 35.11
Other 3.09 2.68 10.66 9.78 14.95 13.70 15.30 15.56
Hospital category 2007 2008 2009 2010 Hospital category 2011
University 36.43 34.83 35.50 40.83 MPHAT 40.45
First-rate municipal 44.13 42.15 41.20 41.87 SHAT 42.59
Urban 37.75 33.89 28.80 33.17 other specialized 7.33
Municipal 42.84 40.75 40.89 43.30 Private healthcare facilities 32.12
Specialized obstertrics and gynecology 26.06 23.12 29.21 29.07 Psychiatric 5.72
Specialized pediatric 75.41 70.75 71.51 62.85 Centers (onco-/psych-/dermatology and venerology) 12.02
Other specialized 28.98 28.80 27.45 25.09 Hospitals to other administrations 20.73
CMSCC 36.12 29.10 35.87 45.83 Other 0.09
Other 19.82 16.83 15.54 0.10 CMSCC 38.08

Table 2: Percentage of treated with antibiotics patients by hospital category for the period 1999-2011.

VAP bacteriologically unconfirmed Number 26 % 2.8
unexamined 6 0.6
Pulmonary infections bacteriologically unconfirmed 580 18.3
unexamined 906 28.6
SSIs bacteriologically unconfirmed 217 6.4
unexamined 46 1.4
Cardiovascular system infections bacteriologically unconfirmed 116 24.0
unexamined 289 59.7
UTIs bacteriologically unconfirmed 186 6.7
unexamined 59 2.1
Sepsis bacteriologically unconfirmed 38 4.2
unexamined 4 0.4

Таble 3: Percentage of unconfirmed and unexamined microbiologically infections (some principal ni groups) in 2011.

The microbiologically identified infections have maintained their characteristics in the course of years. E. Coli and S. aureus have been isolated as principal microbial agents, determining together one third of the infections. For instance for the last 5 years (2007-2011). E. Coli has been isolated annually in 18-17%, S. aureus in 13-15% of the infections. ?hese microorganisms have been isolated in the highest percentage according to USA Surveillance Network data as well-17-19% ?f the bacterial isolates from inpatients between 1998-2005 (Figure 2) [4].

bacteriology-parasitology-Frequency-bacterial

Figure 2: Frequency of bacterial species in individual specimen from inpatients between 1998-2005. Total of 3,209,413 isolates (The Surveillance Network- USA).

Among the most frequent microbial agents, isolated in infections treated as nosocomial ones are a number of Gram-negative bacteria, pertaining to the so-called conditionally pathogenic1 or oppotunistic bacteria2, known for the multiresistance of their hospital strains [5-11]. The participation of Gram-positive microorganisms as coagulasenegative staphylococci (CoNS) to this group has recently been emphasized, particularly in cases of central venous catheter related infections [4,9].

In the course of the period studied from 1999 t? 2011 the isolates of opportunistic bacteria determine a stable and even a rising percentage as follows:

• Isolated in increasing percentage:

Klebsiella spp, predominantly K. ?neumoniae-8 t? 12%, for the last 2 years 14-12%;

Acinetobacter spp, with a leading causative agent of the species-A. baumannii-7 t? 9%;

Enterococcus spp with the greatest number of isolates of Enterococcus faecalis from 4 to 8%;

• Of comparatively stable isolation level:

− The isolation level of P. aeruginosa has been maintained at 10%; Proteus spp, mainly P. mirabilis; ?nterobacter spp, ?f which the highest number of isolates of ?nterobacter cloacae-each of the species of about 4-5%; Serratia spp, exclusively strains of Serratia marcescens 1-2%;

− Coagulase-negative Staphylococci(in a considerable percentage S. epidermidis) 6-8%.

NI by wards

Overall incidence rates, rates by principal infection sites, percentage distribution by infection sites

Pediatric wards: The neonatal intensive care units (NICUs) are classified under the categories prematures (preterms) and hypothrofic infants up to 2010, and in 2011 under the category of preterms, comprising the previously distinguished category of the hypothrofic infants.

The follow up in the course of the period studied has demonstrated the importance of the following NI groups for the pediatric wards:

Up to 2010 the AURTIs in fact determined the greatest part of the reported infections by these wards. With the falling off of this category as a separate nosologic group in 2011 the overall incidence rate declines to 16.3% in the neonatal wards (term infants), NICUs-0.0%, infants up to 1 year of age-3.5%, and in the general profile and internal pediatric wards-4.2% (Table 4).

Wards 1999 2000 2001 2002 2003 2004 2005 2006
Neonatal 27.8 20.2 17.2 20.1 22.3 19.3 21.3 20.2
Nicu 227.4 123.2 213 221.4 308.2 193.6 206.2 278.3
Hypothrophic 513.8 344.8 144.2 435.8 381.1 78.1 129.3 487.3
Nurselings 29 66.8 38.8 28.4 25.3 20.7 30.1 60.2
General profile 43.2 57.4 47.9 43 41.8 36.1 23 32
Internal 17.2 17.9 18.6 24.4 20.2 14.2 9.4 12.2
Wards 2007 2008 2009 2010 Wards 2011
neonatal 21.4 20.4 16.6 17.5 Neonatal 16.3
NICU 393.8 368 419.9 186.4 NICU, Hypothrophic 0
hypothrophic 513.2 367 259.7 300.7    
Nurselings 43.9 31.4 30.8 12.1 Nurselings 3.5
General profile 32.8 22.2 24.4 25 Pediatric 4.2
Internal 12.5 10.2 14.1 9.8    

Таble 4: NI overall incidence rate (per 1000 patients discharged) in the pediatric wards, 1999-2011.

A considerable number of AURTIs have been notified yearly incorrectly under the category of pulmonary infections, the latter including, on account of IDC3 only infections of the lower respiratory tract as bronchitis, bronchiolitis and pneumonia. Thus the percentage and the rates of the lower respiratory tract infections (LRTIs) have been artificially exaggerated. For example, up to 2010 LRTIs comprised the highest proportion of the notified infections in the neonatal wards (16- 17%), infants 16-17%; NICU 10-23%*. The rates for NICU, for instance, have been varying within broad limits, mostly within higher values, i.e. NICU-16-84%, hypothrophic infants 9-85% respectively (Table 5). The exclusion of AURTIs as a separate classification group led to a considerable decrease in the rates in 2011. The incidence in the infants’ wards, ranging between 2.5 and 11% till 2010 decreases to 0.6% in 2011, in the pediatric therapeutic wards (general profile) the rate varying within the range of 4-11% till 2010 is reduced to 1.1% in 2011 (Table 5).

 Wards 1999 2000 2001 2002 2003 2004 2005 2006
Obstetrics and gynecology (O&G) – general  profile 0.1 0.0 0.1 0.2 0.3 0.1 0.0 0.0
Neonatal 1.6 0.9 1.4 3.2 2.5 1.5 3.1 3.7
Nicu 19.7 15.6 24.0 27.5 53.8 19.9 33.6 23.7
Hypothrophic 84.8 64.0 25.8 91.9 34.5 9.4 26.0 45.7
Nurselings 4.4 11.1 1.8 3.2 3.2 2.8 3.7 11.7
General profile 8.4 11.4 8.5 8.5 7.0 7.9 3.9 7.8
Internal 1.0 3.6 2.7 3.6 2.8 2.3 0.5 0.8
Wards 2007 2008 2009 2010 Wards 2011
O&G – general  profile 0.1 0.0 0.0 0.0 O&G – general  profile 0.0
Neonatal 0.04 3.6 2.6 2.8 Neonatal 2.6
NICU 81.4 83.7 57.0 29.9 NICU, hypothrophic 0.0
Hypothrophic 76.3 32.0 20.5 6.7    
Nurselings 6.6 5.0 6.3 2.5 Infants 0.6
General profile 4.9 3.8 4.1 4.7 Pediatric 1.1
Internal 3.1 1.3 1.3 1.0    

Таble 5: LRTIs (pulmonary infections) incidence rate (per 1000 patients discharged) in the pediatric wards, 1999-2011.

The follow up in the course of the period studied have demonstrated the importance of the following NI groups for the pediatric wards (Tables 5-7).

Wards 1999 2000 2001 2002 2003 2004 2005 2006
Obstetrics and gynecology (O&G)– general  profile 0.2 0.9 0.0 0.0 0.0 0.3 0.1 0.3
Neonatal 0.1 0.2 0.4 0.2 0.4 0.6 0.7 0.4
NICU 6.3 3.0 6.5 7.8 7.7 16.7 12.0 10.1
Hypothrophic 31.1 16.6 6.9 6.3 6.4 2.0 6.1 2.5
Nurselings 0.1 0.4 0.1 0.4 0.5 1.0 2.0 1.0
General profile 1.3 0.9 1.6 1.0 1.0 0.9 0.6 0.5
Internal 0.1 0.3 2.0 0.5 1.1 0.4 1.4 0.1
Wards 2007 2008 2009 2010 Wards 2011
O&G – general  profile 0.2 0.2 0.4 0.1 O&G – general  profile 0.3
Neonatal 0.5 0.4 0.1 0.3 Neonatal 0.2
NICU 10.8 11.0 11.7 9.0 NICU, hypothrophic 0.0
Hypothrophic 0.0 7.4 4.5 10.1    
Nurselings 0.3 0.6 0.6 0.0 Infants 0.0
General profile 0.5 0.5 0.6 0.6 Pediatric 0.3
Internal 0.1 0.1 0.0 0.1    

Таble 6: UTIs incidence rate (per 1000 patients discharged) in the pediatric wards, 1999-2011.

Wards 1999 2000 2001 2002 2003 2004 2005 2006
Obstetrics and gynecology (O&G)–general  profile 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1
Neonatal 1.4 1.5 0.7 0.9 0.8 0.4 1.3 1.0
Nicu 0.0 0.7 1.6 0.0 0.0 0.0 0.0 0.0
Hypothrophic 0.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0
Nurselings 0.1 0.2 0.0 0.0 0.1 0.2 0.0 0.1
General profile 0.0 0.0 0.1 0.1 0. 1 0.1 0.0 0.0
Internal 0.0 0.1 0.1 0.0 0.0 0.0 0.0 0.2
Wards 2007 2008 2009 2010 WARDS 2011
O&G – general  profile 0.0 0.0 0.0 0.0 O&G – general  profile 0.0
Neonatal 0.9 1.0 1.0 0.8 Neonatal 1.2
NICU 0.0 1.7 0.8 0.5 NICU. hypothrophic 0.0
Hypothrophic 0.0 0.0 0.0 0.0    
Nurselings 0.3 0.0 0.0 0.0 Infants 0.0
General profile 0.1 0.0 0.1 0.1 Pediatric 0.3
Internal 0.0 0.0 0.2 0.1    

Таble 7: Sepsis incidence rate (per 1000 patients discharged) in the pediatric wards, 1999-2011.

Enteric infections: Amount to about 7-12% of the reported infections in the neonatal wards, infants 2-8%, pediatric wards-3-19%*. In 2011 there has been a noticeable increase in the enteric infections in the infants’ wards (up to 50% of the registered infections), due to enteroviruses epidemic distribution.

Skin infections: The percentage is higher (5-18%) for the neonatal wards in relation to eventual possibility for dissemination, compared to NICU 0-4%, infants/pediatric (general profile) wards 0-2/3%*.

Infections of the sense organs, usually referring to conjunctivitis: Outbreaks of bacterial conjunctivitis, predominantly staphylococcal in the past, for the time being are not registered. However, these infections still comprise the highest percentage of the reported infections in the neonatal wards 30-40%. In NICU and the infants wards the conjunctivitis are more rarely encountered-NICU 3-14% of the registered infections, infants 1-3%, with exceptions in years of epidemic outbreaks, e.g, in 2011 these infections in the infants wards reached 12.5% of the reported infections, due to distribution of viral conjunctivitis*.

UTIs: The UTIs comprise 1-3% of the NI in the neonatal wards, 3-9%-NICU*. The rates are within low limits for the neonatal/pediatric wards 0.2-0.3%, and higher and variable for NICU (NICU-3 t? 17%, NICU-hypothrofic children 0.0-31.1%), in the neonatal intensive care wards urinary catheterization procedures should be considered (Table 6).

Sepsis: The single cases reported in separate years by the pediatric wards determine very low incidence rate level of the order of 0.8 t? 1.2%-neonatal wards, 0.0-1.7%-NICU, 0.0-0.5%-hypothrophic, 0.0–0.3%-infants, 0.0-0.1% general profile, 0.0-0.2% internal pediatric wards (Table 7).

Cardiovascular infections have not been registered by the neonatal/ infants wards, several single cases have been reported by the wards for elder children.

*The complete set of tables with the numerical data by years for the 1999-2011 period is available with the editors.

Anesthesiology and resuscitation, intensive therapy [(intensive care units (ICUs)] and surgical wards

The nomenclature of the wards till 2010 included the following separate categories: Anesthesiology and resuscitation intensive care unit (ARICU), ARICU-neurosurgery, pediatric, medical intensive care unit. Since 2011 these wards are classified into the general categories: “anesthesiology and resuscitation (A&R)” and “intensive therapy (IT)”, the latter comprising the intensive care units (ICUs).

Compared to the previous period the 2011 overall incidence rate for the high-risk A&R and IT units does not differ substantially: anesthesiology and reanimation-73%, intensive therapy (IT)-26%, burns-123% (Table 8).

Wards 1999 2000 2001 2002 2003 2004 2005 2006
ARICU 110.3 195.3 100.8 86.8 67.1 72.1 72.7 94.8
ARICU-neurosurgery 87.5 70.7 80.8 124.1 134.0 110.2 107.9 60.2
Pediatric ICUs 46.7 56.7 18.1 43.4 12.8 21.0 43.3 36.0
Surgical-general profile 13.7 15.0 14.2 11.1 11.5 10.1 11.9 14.8
Orthopedics and traumatology 11.4 10.2 8.3 9.1 8.3 6.1 7.4 9.0
Neurosurgery 17.1 18.8 17.5 14.2 12.8 16.0 11.8 14.8
Cardiovascular surgery 23.8 20.2 18.0 21.9 22.3 12.5 15.6 12.8
Urology 41.0 40.9 39.3 33.9 30.7 30.1 34.8 32.3
Pediatric surgical- 11.0 11.4 10.2 9.0 12.4 7.1 12.7 17.0
Burns 58.7 59.3 95.0 98.5 91.6 80.2 58.8 62.5
Other                
Gynecology 2.9 2.4 3.8 3.1 3.3 2.7 4.8 5.4
Oncology 4.6 2.5 3.2 4.8 3.0 3.9 3.8 3.6
Internal – general profile 6.5 4.5 4.6 3.8 5.0 2.5 2.7 2.9
Neurology 13.6 12.9 12.8 10.0 7.2 5.5 5.0 4.3
Psychiatry 45.7 41.2 26.3 27.2 25.1 17.5 23.1 16.9
Wards 2007 2008 2009 2010 Wards 2011
ARICU 97.8 82.3 69.4 60.8 Anesthesiology and resuscitation (A&R) 73.0
ARICU-neurosurgery 40.3 35.8 83.9 123.5    
Pediatric ICUs 24.6 30.6 55.5 41.0 Intensive therapy (IT) 25.6
Surgical-general profile 13.0 11.2 12.1 13.1 Surgery 13.5
Orthopedics and traumatology 8.6 5.9 7.3 8.1 Orthopedics and traumatology 7.4
Neurosurgery 12.7 13.9 15.8 11.0 Neurosurgery 9.7
Cardiovascular surgery 11.4 11.7 13.0 14.6 Cardiac surgery 31.3
          Vascular surgery 13.0
Urology 25.7 27.7 21.4 21.4 Urology 16.9
   Pediatric surgery 13.7 13.2 14.0 13.4 Pediatric surgery 14.0
          Septic surgery 24.3
Burns 53.5 39.2 48.9 89.9 Burns 122.8
Other         Other  
Gynecology 6.4 6.1 6.0 6.7 Gynecology 8.5
Oncology 2.2 2.1 2.2 3.7 Oncology 5.1
Internal – general profile 2.8 2.9 2.5 2.2 Internal – general profile 2.1
Neurology 4.2 3.4 4.1 4.4 Neurology 2.9
Psychiatry 19.4 15.1 10.5 9.8 Psychiatry 6.7

Таble 8: Overall NI incidence rate (per 1000 patients discharged) in resuscitation, ICUs and surgical wards, 1999-2011.

The subdivision of “cardiovascular surgery” to cardiac surgery and vascular surgery provides a possibility for a more exact idea about the overall infections level-for 2011 33% and 13% respectively. The rate for septic surgery units (in view of dirty and infected wounds treatment) is 24%, and in the rest special surgery wards-between 10% and 17% (Table 8).

VAP/LRTIs (pulmonary infections)

An important element is the introduction of VAP in the reporting system at the basis of:

- VAP was confirmed as the most serious complications in patients on mechanical ventilation (according to the references in 8-28%, and in particular critically ill patients on cardiopulmonary resuscitation) [12].

- This type of pulmonary infection is related to high mortality rate from 24 to 50%, which may reach 76% in some specific wards, or when the pulmonary infection is caused by pathogens the identification of which in tracheobrochial aspirate samples is related to a high risk of infection development, the so called “highrisk pathogens” [13-15].

The reason for VAP introduction as a separate infection category was an avoidance of formal reporting. For the period 1999 to 2010 about 30-50% of the registered infections in ARICUs and ICUs were pulmonary ones, AURTIs incorrectly registered under this category: ARICUs 36-44%, ARICU to the neurosurgery 17-46%. In 2011 VAP already amounts to 20% ?f the infections in each of these two types of wards-A&R and IT respectively, the pulmonary infections non-related to mechanical ventilation 26-31% respectively*. The compared rates VAP/pulmonary infections amount to: A&R-15/19%, IT-5/8%. Special surgery wards having indicated VAP /pulmonary infections are cardiac surgery-4/18% ?f all NI (1.2/5.6%), thoracic surgery-5/30% (0.7/3.9%), pediatric surgery-4/7% (0.6/0.9%), the rates for the rest surgical wards being within 0,0-0.9%o on the basis of single notified cases (Table 9).

Wards 1999 2000 2001 2002 2003 2004 2005 2006
ARICU 39.3 33.0 34.9 38.1 29.9 29.3 27.1 35.3
ARICU-neurosurgery 21.1 34.6 17.9 44.2 45.2 33.2 49.4 23.2
Medical ICUs 0.4 3.7 4.3 2.3 2.6 1.0 2.4 2.3
Pediatric ICUs 6.7 11.1 2.5 1.1 1.8 1.7 2.5 4.0
Surgical-general profile 0.8 0.5 0.5 0.5 0.4 0.6 0.4 0.6
Orthopedics and traumatology 0.4 0.7 0.6 0.6 0.2 0.1 0.4 0.3
Neurosurgery 0.9 1.3 0.6 0.2 3.2 7.0 0.9 1.7
Cardiovascular surgery 0.4 2.7 3.1 2.3 5.2 2.1 3.7 3.1
Urology 0.4 0.2 0.1 0.1 0.3 0.4 0.3 0.4
Pediatric surgery 1.2 1.3 1.0 1.1 0.9 0.3 0.8 0.4
Burns 7.7 7.7 18.0 8.8 5.1 4.2 3.5 2.6
Other                
Gynecology 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Oncology 1.0 0.7 0.6 1.0 1.0 0.5 0.3 0.4
Internal – general profile 6.5 7.2 5.2 4.5 2.8 1.6 1.8 1.6
Neurology 9.6 9.2 3.9 4.8 3.9 2.7 3.9 2.6
Psychiatry                
Wards 2007 2008 2009 2010 Wards 2011
VAP Pulmonary infections
ARICU 34.4 28.3 24.9 25.4 Anesthesiology and resuscitation (A&R) 14.6 18.7
ARICU-neurosurgery 11.8 10.8 28.0 39.0      
Medical ICUs 1.2 1.9 1.0 1.6 Intensive therapy (IT)  5.0  7.9
Pediatric ICUs 3.7 3.6 7.0 7.1      
Surgical-general profile 0.6 0.4 0.4 0.5 Surgery  0.03  0.3
Orthopedics and traumatology 0.2 0.1 0.3 0.1 Orthopedics and traumatology 0.0 0.1
Neurosurgery 1.5 1.4 2.0 1.9 Neurosurgery 0.0 0.7
Cardiovascular surgery 3.2 2.9 2.6 2.0 Cardiac surgery 1.2 5.6
          Vascular surgery 0.07 0.0
Urology 0.3 0.1 0.1 0.1 Urology   0.0 0.08
Pediatric surgery 0.6 1.2 1.1 1.6 Pediatric surgery 0.6 0.9
          Septic surgery 0.0 0.0
          Thoracic surgery 0.7 3.9
          Lastic surgery 0.0 0.0
          Facio-maxillary surgery 0.0 0.0
Burns 5.2 1.4 2.9 4.9 Burns 0.0 5.0

Таble 9: Incidence rate of vap and pulmonary infections (per 1000 patients discharged) in resuscitation. ICUs and surgical wards. 1999-2011.

SSIs: All surgeries report SSIs as a basic nosocomial complication: These infections constitute the major part of the reported infections, varying from 11%-urology, 13%-cardiac surgery to 30%-burns, pediatric surgery, neurosurgery, 50%-thoracic surgery, plastic surgery, 70-80% general surgery, orthopedics and traumatology, 82% faciomaxillary surgery, 86%-vascular surgery, 96%-septic surger*. Wards with definitely higher incidence are the burns units-38%, septic surgery-23% and vascular surgery-11%, while in the other special surgeries the rates are within lower limits 2-9%, ARICUs/ICUs-6/3% (Table 10).

  SSIs
Wards 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Wards 2011
ARICU 18.2 11.0 12.9 10.4 8.1 7.7 7.2 10.4 11.2 8.6 5.8 5.7 Anesthesiology and resuscitation (A&R) 6.3
ARICU-neuro surgery 17.9 2.5 19.3 7.0 20.1 7.9 11.6 2.0 3.1 2.0 0.2 4.6    
medical ICUs 0.1 0.0 0.1 0.1 0.1 0.0 1.6 0.0 0.0 0.1 0.0 0.0 Intensive therapy (IT) 2.7
pediatric ICUs 4.7 13.6 3.3 27.9 3.8 3.7 1.3 1.0 0.2 1.6 4.8 6.0    
Surgical-general profile 8.7 10.7 10.3 7.6 7.3 6.9 8.7 9.9 8.9 7.8 8.4 8.7 Surgery 9.4
Orthopedics and Traumatology 8.6 7.0 6.3 6.8 6.5 4.6 4.9 6.4 6.7 4.6 5.2 6.1 Orthopedics and traumatology 5.7
Neurosurgery 6.9 7.0 6.7 8.1 4.6 3.4 3.9 5.4 3.5 2.4 3.2 2.4 Neurosurgery 2.6
Cardiovascular surgery 17.1 14.0 9.6 8.8 8.6 6.5 4.5 5.6 4.2 4.2 4.7 5.0 Cardiac surgery 4.2
                          Vascular surgery 11.3
Urology 6.0 6.5 6.3 7.5 5.7 3.8 4.9 4.5 3.4 3.2 2.8 2.5 Urology 2.0
Pediatric surgery 4.5 4.9 4.3 3.4 2.8 2.6 6.3 5.9 8.3 5.6 5.9 3.7 Pediatric surgery 4.2
                          Septic surgery 23.4
                          Thoracic surgery 6.7
                          Plastic surgery 3.9
                          Facio-maxillary surgery 1.8
Burns 46.7 35.2 47.2 40.2 37.3 40.5 31.9 36.8 26.0 17.2 21.7 29.7 Burns 37.9

Таble 10: Incidence rate of SSIs (per 1000 patients discharged) in resuscitation. ICUs and surgical wards. 1999-2011.

UTIs: They comprise the greatest part (78%) of the reported infections in the urological wards and 18%/10% in risk wards as anesthesiology and resuscitation/burns units*, but the rates are analogous-resuscitation/urology-13/13%, burns-12%, indicating similar level of the infections among the A&R and burns units patients, and the level of the infections among patients of the urological wards with urological problems (Table 11). The rates are presumably dependent and specifically related to urinary catheterization procedures (indwelling catheter) performed in these types of wards.

  UTIs
Wards 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010   Wards 2011
ARICU 14.3 13.3 12.5 13.8 10.9 10.5 8.6 15.3 14.2 13.5 10.2 8.8 Anesthesiology and resuscitation (A&R) 13.5
ARICU-neuro surgery 36.2 54.8 22.2 21.7 11.0 23.6 29.0 15.4 12.9 7.1 15.3 25.7    
Medical ICUs 0.4 0.9 0.6 0.4 1.1 0.5 0.5 1.2 2.0 1.3 0.7 0.6 Intensive therapy (IT) 2.3
Pediatric ICUs 7.9 7.5 2.1 3.3 1.3 1.6 6.3 11.6 7.6 5.5 5.0 4.2    
Surgical-general profile 0.6 0.9 0.9 0.8 0.9 0.5 0.6 0.7 0.7 0.7 0.6 0.9 Surgery 0.9
Orthopedics and Traumatology 0.4 0.8 0.6 0.7 0.6 0.5 0.7 0.9 0.6 0.6 0.6 0.6 Orthopedics and traumatology 0.6
Neurosurgery 6.9 7.1 6.8 4.2 3.5 4.3 3.1 4.1 3.9 2.4 2.2 1.0 Neurosurgery 1.7
Cardiovascular surgery 0.4 0.1 1.5 2.1 3.5 0.7 3.6 1.4 1.5 0.8 1.6 2.4 Cardiac surgery 5.5
                          Vascular surgery 0.4
Urology 33.9 32.7 32.0 25.3 23.9 23.9 27.9 25.3 20.9 22.9 17.2 17.2 Urology   13.1
Pediatric surgery 0.3 0.3 0.1 1.1 0.7 0.1 0.3 0.9 0.9 0.1 0.4 0.0 Pediatric surgery 0.5
                          Septic surgery 0.9
                          Thoracic surgery 0.4
                          Plastic surgery 0.0
                          Facio-maxillary surgery 0.0
Burns 17.3 18.9 30.2 11.3 14.3 5.0 3.7 5.8 4.0 3.2 4.0 4.9 Burns 12.0

Таble 11: Incidence rate of UTIs (per 1000 patients discharged) in resuscitation. ICUs and surgical wards. 1999-2011.

Sepsis: The 2011 notified cases comprise 11% of the NI reported by the anesthesiology and resuscitation, about 20-21% by the intensive therapy (ICUs), cardiac and pediatric surgery, 18%-burns units, in the rest surgical wards the percentages vary considerably between 0-9%*. The risk of septicaemia outlines as a highest one in the burns units-22%. The official registration data, based on adequacy of the reporting, indicate an incidence in A&R/IT/cardiac surgery of 8/5/6%, pediatric surgery-3%, the rest surgery profiles, 0.0-0.5% (Table 12).

  Sepsis
Wards 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Wards 2011
ARICU 12.4 8.0 9.5 6.8 3.8 7.6 6.9 6.0 9.8 5.8 5.8 5.7 Anesthesiology and resuscitation (A&R) 8.0
ARICU-neurosurgery 6.4 1.5 17.2 9.8 19.6 15.7 12.8 7.2 6.3 7.1 22.6 27.1    
medical ICUs 0.8 0.8 0.4 0.2 0.2 0.0 0.2 0.3 0.2 0.2 0.1 1.0 Intensive therapy (IT) 4.9
pediatric ICUs 15.4 8.0 3.7 2.5 2.5 4.3 5.8 6.6 2.9 5.5 15.1 9.9    
Surgical-general profile 1.2 0.8 0.8 0.1 0.2 0.3 0.3 0.3 0.3 0.2 0.2 0.2 Surgery 0.3
Orthopedics and Traumatology 0.1 0.0 0.1 0.1 0.2 0.1 0.1 0.0 0.1 0.1 0.0 0.0 Orthopedics and traumatology 0.0
Neurosurgery 0.6 0.5 0.6 0.3 0.3 0.4 0.3 1.2 1.2 4.2 2.3 1.5 Neurosurgery 0.7
Cardiovascular surgery 2.4 0.7 3.2 3.4 4.1 1.3 1.4 0.9 1.0 1.1 0.7 1.1 Cardiac surgery 6.2
                          Vascular surgery 0.3
Urology 0.7 0.7 0.5 0.3 0.3 0.5 0.5 0.3 0.2 0.2 0.3 0.5 Urology 0.5
Pediatric surgery 0.9 1.5 1.8 0.6 0.6 0.8 0.4 0.5 0.5 0.3 1.1 1.9 Pediatric surgery 2.9
                          Septic surgery 0.0
                          Thoracic surgery 0.2
                          Plastic surgery 0.0
                          Facio-maxillary surgery 0.2
Burns 21.6 21.9 26.0 28.4 22.1 17.9 7.5 7.9 9.6 8.2 6.4 9.9 Burns 21.9

Таble 12: Incidence rate of sepsis (per 1000 patients discharged) in resuscitation. ICUs and surgical wards, 1999-2011.

Two other categories of infections are considered of special importance for the A&R, the IT, and the surgery as follows:

Intra-abdominal infections, as complications of operative procedures, related to a risk of high mortality rate, and infections of the cardiovascular system (phlebites, thrombophlebites to the greatest part, related to vascular devices). In the course of the period are reported single cases, the registration being improved in the last year: intraabdominal infections-5% ?f the infections in resuscitation, ICUs, general surgery, and 11%-pediatric surgery; cardiovascular system infections-22% in neurosurgery, 7% in cardiac surgery, 3-4% vascular, pediatric surgery, 2%-resuscitation, ICUs, general surgery*.

Discussion

The adopted in the country official registration system sustains the responsibility of the medical personnel on the problems of NI surveillance and control. CIS-NI provides considerable generalized and non-complicated information about NI distribution on the basis of the official records, processed in the national health health information center.

The analysis of the overall NI incidence rates is indicative of a comparatively similar level of the registration by years in the course of the period observed-1999 to 2011. When calculating nosocomial infections incidence rate we utilize for the present a more general denominator (patients discharged), while some studies and the reference data of National Nosocomial Infections Surveillance System, USA (NNIS), subsequently National Healthcare Safety Network, USA (NHSN), engage more precised indices in the form of percentiles [15,16]. The recommended incidence rate calculation is per 1000 patient-days: as regards VAP-ventilator-days; vascular catheter related bacteremias-central line-days, umbilical catheter-days respectively; UTIs-urinary catheter-days. It is evident that no comparison can be made with these internationally approbated and adopted indices, but the calculated on a more general basis (per 1000 patients discharged) incidence rate is nevertheless a comparable by years morbidity rate index, while the percentage (frequency distribution) does not allow such type of interpretation.

There exist real possibilities for improving the feed-back to the wards by ensuring additional links to the system for the comparison of indices, treating the care for high-risk patients, i.e. undergoing risk procedures. These data should be strictly defined by specialty of the wards, i.e. patients undergooriginal data of the wards with the generalized data of the wards of similar activity (speciality), eg., A&R units differentiated by their affiliation to the specific surgery ward, IT (ICUs) units-strictly differentiated by intended activity. There should be used comprehensible and reliable statistical criteria adjustable to the medical expertise in case of need.

The introduction of VAP in 2011 as a separate category established a 5% percentage of this infection of all the NI notified in the country. As a matter of comparison ?imberly-Clark Health Care clinical practice guidelines indicate a considerably higher percentage of VAP amounting to 15% of all nosocomial infections, and 24% to 27% ?f the infections acquired in coronary artery surgery and medical intensive care units (mICUs) respectively [17]. The initial incidence data for our country as of 2011 vary within the limits of about 15% for A&R, 5%-IT, 1,2%-cardiac surgery, and single or no cases notified by all the other special surgeries. The definite rates of VAP should be followed up in the units engaged with attending of intubated patients, and by this reason specifically subject to control.

The microbiological diagnostics is of substantial importance for the NI control in two respects:

The rapid and accurate diagnostic tests provide a possibility for correct treatment of the patient at the onset of infection; the microbial dissemination, most often referring to multiresistant bacteria, is prevented [18]. The distribution of the isolates in the microbiologically identified infections (total number of isolates) in the country is conformable to references data, E.coli and S. aureus being the principal etiologic agents. The unconfirmed and unexamined microbiologically infections, however, comprise a non-negligible percentage 3-10% of the reported VAP, SSIs, UTIs ansd sepsis respectively, more than 40%-of LRTIs cases, and more than 80% of cardiovascular infections. The improvement of the diagnostics through equipment with rapid tests, and the strict requirement for microbiological sampling and testing, antibiogram including, of any case of proved serious impact over the underlying disease, would eventually contribute to a better microbiological diagnosis and treatment of patients.

The examination of the dynamics of the indices for the two distinguished subcategories of wards revealed some serious weak points. For instance the low level of registration in NICU with no reported infections in 2011 may be considered unjustifiable in view of the lifesaving invasive manipulations performed in these high risk neonatal units as umbilical vein catheterization (umbilical catheter), intubation or continuous positive airway pressure (CPAP) in newborns with asphyxia and/or respiratoy distress syndrome (RDS), and other risk procedures as gastric aspiration, urinary catheterization etc.

The cases of sepsis report bacteremia, without indicating, however, its origin (primary, secondary), and especially its relation to installed vascular device for central or peripheral venous catheterization. The available information may be considered indicative, though to a great extent dependent on adequate registration. The data in the course of the period 1999 to 2011 demonstrate the importance of these infections for the burns units, resuscitation wards, the neurosurgical resuscitation (data up to 2010), ICUs, cardiac and pediatric surgery.

Conclusion

The official registration system provides reliable information on a national level for the purpose of NI surveillance and control. The system interpretes the original data of the wards in basic indices as incidence rates and microbial isolates distribution. This official database reflects the efforts in the sphere of NI prevention and control. Possible additional links to the system would contribute to direct comparisons of indices regarding the care for patients undergoing risk procedures.

1Conditionally pathogenic bacteria are only pathogenic under certain conditions, such as a wound that allows for entry into the blood, or a decrease in immune function [5].

2Opportunistic microorganisms are usually found in the environment or as part of the normal flora. In normal individuals, they are harmless, but they may cause severe disease in immunocompromised patients or if they penetrate a territory from which they are usually excluded (as a result, for example, of trauma or surgery) definition adapted by G. Virella [6]. Both terms are usually compatible.

3International Disease Classification

References

Citation: Todorova-Christova M, Vatcheva R, Filipova R, Kamenova T, Arnaudov Y, et al. (2015) Nosocomial Infections Incidence Rates, Bulgaria, 1999-2011. J Bacteriol Parasitol 6:218.

Copyright: © 2015 Todorova-Christova M, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.